For #2, if he was on a work visa for sure (or undocumented or honestly even a green card holder at this point), I would say if it's within your purview to keep him technically employed for immigration purposes maybe you ethically should, even if it requires reducing shifts or something to keep stuff covered. But if he's second-generation, then like some of the commenters mentioned, he's probably a birthright citizen, and when they get to the point of deporting/interning birthright citizens, it doesn't matter to the people doing it if they have a job.

That doesn't mean you fire him immediately necessarily; give him the same leeway, counseling, etc. you might give any other employee who might be currently under a lot of outside stress. But it sounds like you already did that and more, and you shouldn't have to worry that firing him will cause immediate bad consequences to him beyond being fired.