I wouldn't expect HR to do anything, nor would I expect them to send out a mail if someone quit or were fired. I do think the right thing is for the manager to

I wouldn't expect HR to do anything, nor would I expect them to send out a mail if someone quit or were fired. I do think the right thing is for the manager to acknowledge the situation and maybe hold some kind of gathering in remembrance. Possibly even pull together something to send to the family of the deceased. But I don't think this means anything coming from HR, it's gotta come from people who knew the person.