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?”…