Yes.
I think more often than not (although I only have anecdotal knowledge) there are no signs that a suicide is imminent. A person may be known to be depressed and working on it and seeming well, or there may be no signs whatsoever, and everyone is taken by surprise. I think we need to be very careful when suggesting that signs must have been missed, because it suggests that blame should be laid somewhere when it should not.
“A” is lucky to have your H at school - he can play the role of supporter, protector, speaker - whatever is necessary to help “A” along.
Sometimes while we don’t notice any “signs” you might wonder if his close family did - or did not. We often don’t want to talk about our fears about our kids or imperfections. But also entirely possible that their son did not share any difficulties he was having.
Prayers for all.
Even when there are signs, stopping a determined person is nearly impossible.
For the dad, trying to get back to work immediately, especially in a job like teaching where you are always “on,” may be nearly impossible. An idea, which your H may not be comfortable with: Could your H ask confidentially if there are provisions for paid leave at the school for cases like this? Maybe someone in HR could look at the dad’s accrued PTO (not sharing that info with your H, but perhaps reaching out to the dad) in case there are options that would give the dad at least a few weeks away from school. Some time to grieve with his wife out of the public eye, so to speak, might be helpful.
For 4 years, I’ve been haunted by a boy that I only met once. He arrived at our neighbor’s house to pick up their daughter for the senior prom and parked by our house. He stopped to talk about azaleas that I was transplanting and remarked on how beautiful they were. He was an exceptionally good looking kid with an easy way about him. I remember thinking how lucky the girl was next door to have only just met this boy and yet already be going to the prom with him. Two weeks later, he took his own life with a gun while sitting upstairs in the bedroom while his two sisters were downstairs in the living room. I didn’t even know him and i still can’t believe it.
Making sure the family has food, and has help with the daily tasks of life like laundry, care of small children, grocery shopping, housecleaning when they’re overwhelmed with grief: that is meaningful support. Offering time and a sympathetic ear to siblings of the person who took their own life is also meaningful support; they’ll be grieving while not knowing how to deal with their parents’ grief.
Coincidental - a photo of my nephew from 2013 just popped up as a Facebook memory. Like a punch in the chest, even after all this time. 
I’ve known companies that let workers give some of their PTO to people who need more time off for personal reasons than they have available through company policy. Now some people might prefer to go back to work sooner. And you might argue that companies should just have a heart and let people have more time, but there might be things like union contracts that restrict that. But it is something coworkers can do sometimes.
Also important is being there months, years from now. It’s normal for the community to be there with an initial outpouring of support then disappear weeks later while the pain and grief continues.
My sister jumped back into school teaching pretty quickly - her son died on the first day of school for her, her HS freshman son, and her HS senior daughter). She said she didn’t want to sit at home with her thoughts.
DH and I discussed the PTO thing - apparently his district allows teachers to contribute some of their sick leave to a common bank, and then you are permitted to draw from it if you have an extended need. I don’t know if bereavement is applicable, nor if A has contributed to the bank. I’m sure some arrangement could be made for him.
When we saw him after the service, he talked about craving normalcy. The family has been living with a relative while their home is restored to habitability, and absolutely everything in their life is upended. He thought that returning to work would add some needed normalcy to his life. I worry about him holding up, I worry about the students in his classes if he were to break down, but of course it is his decision. He may try it & change his mind.
Oh my goodness - what a situation.
Teaching soon worked out OK for my sister. I think she took off a couple of half-days when she felt like she needed a break.
"I guess I’m struggling to understand how there could have been no signs. "
I wish I could find the website I found years ago describing what a dark hole depression can be and how much energy is spent hiding it. I looked at depression in a whole new light.
Depression was described as a deep black hole that you KNOW you are in but can’t crawl out of.
You KNOW how to act in social situations so can “hide” it easily. You KNOW how to react
We can only know another person’s thoughts and feelings if he or she chooses to share them. So, it actually can be very easy to hide depression or anxiety or anger or plans to kill oneself.
This is a video of Chester Bennington filmed less than 36 hours before he ended his life.
^Wow, that is powerful. Thanks for sharing.
"I guess I’m struggling to understand how there could have been no signs. "
I wish I could find the blog/website I found years ago describing what a dark hole depression can be and how much energy is spent hiding it.
I looked at depression in a whole new light.
From what I learned from the blogger…
Depression was described as a deep black hole that you KNOW you are in but can’t crawl out of. Your mind knows it isn’t right but your emotions don’t match.
Worse yet, there is NO emotion–there is no “feeling” whether good or bad. A void. You don’t feel “happy” and don’t feel “mad or sad” either. Nothing. You act out motions or you just stop…
.If you are mad or upset or sad about an event then you can fight against something but not having “feeling” is just a “null”.
It’s not “not caring” because you have to have feeling to “care”.
Every “what do you have to be down about?” ends with “nothing”. No reason at all. And it’s true.
But you know how to act in social situations so can “hide” it easily. You know what to say, how to react, pretend to care. And it is pretty easy except for the enormous amount of energy expended to do it.
And you WANT to care so hoping to convince yourself. You just don’t.
So according to this blogger( and as sad as it may be) there would be no signs at all.
To help a family in need organize a Meal Train. https://www.mealtrain.com/ Pack lunches for family members.
If you have good penmanship, offer to write thank you notes for memorial donations.
Drive younger children to after-school activities. OP, maybe the coworker would like a ride to work? He may want to return to a routine but could be subject to distracted driving? Or even transportation to a support group meeting.
Okay. I’m dense…or clueless. I don’t understand why saying someone “committed suicide” is offensive and saying someone "took his own life’ is not. It’s hard to get “tone” across. Please believe I’m not trying to be “snarky.” I just honestly don’t understand why the first is offensive.