My son did an internship for a large defense contractor last summer. He didn’t ask the dress code and the middle person coordinating it really wasn’t all that together. So not knowing how to dress we had him wear dress pants, button down and tie on his first day. The rest of the time he wore jeans.
I would interpret it as the employee needing to take a few hours off during the day to go to a funeral.
We used to assume it was because they were going on a job interview.
I’m in non external client handling IT. Everyone on my team would agree with @anomander … funeral!
As it applies to my company, in the midwest, it seems the higher up the development food chain, the further away from business casual it gets. The Software Engineer III’s and up look like they just rolled out of bed and walked into work. The IT lights (SQA’s, System Analysts, etc) seem to dress in mostly jeans and polo/ button up/ sweater. My company has a no t-shirt and tennis shoe policy, but at least 3 devs have on a t-shirt and most of my dept is in tennis shoes.
Not everywhere. Many places are just casual.
great graphic for interpreting today’s dress codes - http://www.bates.edu/career/files/2015/12/dress-code.pdf
My husband is a programmer in CA. He’s never had a dress code. Shorts, Hawaiian shirts and flip flops? No problem. If there was a client in the office, they’d all dress up a bit (khakis, shirt with a collar, real shoes), but aside from that they could wear whatever they wanted.
I remember eyeing a pair of his shorts once because they were old and falling apart (but very comfy!). I asked if maybe that wasn’t pushing the no dress code thing a bit too far. A few days later, I happened to stop by the office and saw the CEO in jeans that were even worse! And no, not the allegedly fashionable pre-ripped look. These were just old, worn out, torn-but-comfy jeans. 
That would be covered under formal social occasions where formalwear is mandatory.
The situation above is also a bit odd as most employers IME would be very understanding enough to encourage the employee to take at least the entire day off or sometimes more if needed.
After finding I got the job in an IS department of a mid-sized Boston area financial firm, my interviewer and later supervisor said while he understood why I wore a suit and tie to the interview to wear business casual in the future for the same reason.
In FL, I’ve been to funerals where men wear bright polo shirts and shorts, sandals. The funeral fits in between golf or tennis. ( but they show their respect, clothes just don’t matter).
Business casual is far too dressed up! Son in Seattle doesn’t even go for polo shirts- clean but more basic T shirts are his norm. Those who work behind the scenes, ie not interacting in person with customers, have no need to worry about what to wear. I feel sorry for those in business with their focus on appearances. Love post #12 response- seems accurate. btw- son was a software developer until he changed companies and became a software engineer. Titles depend on the company- and the job is NOT programmer, there is so much more involved!
Even stodgy old IBM in NY went business casual back in the early 90s except for their consultants. Seattle is more hoodies and flip-flops.
Reporting in from the Boston area – I work at a software company, and my perspective is that there is no need for business casual, casual casual will do.
Observations from both Seattle and Silicon Valley areas: managerial staff might be required to wear nicer jeans (w/o holes)/ khakis and polo shirts, but for lower level employees, the dress code is what Postmodern described in his post. 
I have worked in high tech in the northeast for years (somewhere near Boston). Jeans, t-shirts, clean clothes, no holes in the clothes, no severely worn clothes. Technical conferences are typically the same, although I avoid jeans for long trips only because they are too heavy to carry a lot of them in a suitcase. One time years ago I was going to drop by a wedding on the way back from a technical conference so I had a suit with me. At the last minute I was asked to give a talk to the full conference so I asked the chair “should I wear the suit”. His reply was “no, people will think that you are not technical”.
I suspect that some companies might be different, even radically different. I wouldn’t dress like this for an interview at a bank or investment company, but then I wouldn’t interview at a bank or investment company.
A.K.A.: Don’t dress like Dilbert’s clueless pointy-haired boss…
If you wear a suit as a developer, people will ask you when you have to leave for the funeral.
The best of Silicon Valley: The guy in the kilt. The gal with the green stripes in her hair who would bring a bunny to work.
I’ve been working as a software engineer in the greater Boston area for over 30 years. Some companies are dressier than others. The majority are casual-casual (i.e., sloppier than business casual.) I did interview at a company once which looked “normal” to me because it happened to be Casual Friday. When they proudly mentioned that, I asked what normal attire was. When I heard they wanted dresses and hose (yes, I am female :-), I knew I wouldn’t like working there. (There were also other drawbacks: long commute, having to be on-call.) Where I work now has a lot of people who wear business casual, but it’s not expected and the engineers I respect most tend to dress predominantly in jeans except for rare customer interactions (when they upgrade their attire to business casual.)
I have worked in the financial industry for over 30 years in tech. When I first started a lot of the financial firms were suti and tie if you worked days (I worked nights with my first job, so they didn’t care, and riding the subway home at 2am I certainly wasn’t going to wear a suit). At my second job they wanted jacket and ties, but I was one of the first to go ‘business casual’. Some of the investment banking firms, like Goldman and UBS, were still standard business attire, but since then almost none of them require the business drag unless you are customer facing, and these would be the most conservative of firms. Some companies have no jeans policies, some of them limit things like women wearing flip flops or sandals or shorts, but for the most part in tech no one really cares from everything I have seen and heard. I am a tech manager and I wear Jeans, do wear sneakers or my harness boots, I do wear polo shirts but other people wear t shirts or sweatshirts.
In other words, the idea that the northeast is ‘more formal’ is pretty much an anachronism, I work for one of the largest financial companies in the world these days, and there is no dress code whatsoever, and even the investment banks and the commercial banks aren’t as uptight as they once were. So tell your S not to worry, likely wherever he goes he will find people dressing in ways that would make his grandmother disapprove lol.
Funniest story about this was many years ago, I was in a training class in SF, at the time casual Fridays were common, and a person I made friends with who worked at Silicon Graphics (the folks who made/make the workstations they use for things like CGI in the movies) and someone suggested they have a dress down Friday, and someone asked “what the heck does that mean? We don’t wear underwear?”…
I work for what many would consider a very old-school, stuffy company. When we bring someone from the lab out to meet with customers we actually never tell them what to wear and we get developers showing up wearing everything from jeans to business casual with a sports coat. Customers never bat an eye either way. They’re developers, it’s expected they’re going to do what they’re going to do and we care more about what they say than what they wear.
At the end of the day we’d rather have the charismatic and articulate developer in jeans and a Green Lantern t-shirt vs the stumbling inarticulate guy in Brooks Brothers. And just as a side-comment since this is CC - this is an example of how social skills can affect the career of techies who might think it doesn’t matter. I’ve literally seen executives in my company say, “We’re never putting that guy in front of a customer again.” And that feedback gets back to the poor guy’s management. A couple college classes in debate and advanced English and participating in social clubs / activities in college helps out things like that. Emotional IQ and social skills really are a thing in the corporate world for everyone.