The usual culture would be to stay as mum as possible about anything politics related at work and especially with your boss.

The election result, especially as it pertains to being Muslim, is beyond exceptional. But you might also observe that in exceptional circumstances, people often express support and gratitude for each other widely and openly.

"Hey, I just want to let you know I've appreciated how good of a boss you've been to me."

This will say quite a lot.

Look, business culture sometimes permits the exercise of personal judgment and sometimes political events are devastating to entire cities or communities. But, if you really want to engage in some straight talk, here it is. I know some people are still treating themselves to the fantasy that there was nothing extremely racist or Islamophobic in Trump's election, but the OP's boss probably got the point that he is not welcome here to the president-elect or the president-elect's constituency. The racial slurs being hurled at Muslims across the country might make the point. This isn't a matter of personal responsibility crossing politics: This is a matter of sending a message to the Muslim who happens to work in your office building that he is safe here. I don't know why a boss-worker relationship would ever take precedent over that. Because apparently that's a question they have to worry about now.