Feeling uncomfortable at work

[DaveJ]

2. Report it

You don't want to be in a situation where any of them go on a shooting rampage and you never reported this in advance.

I would hope he would be addressed by a rational supervisor, about what is and isn't appropriate to say, and that he would not immediately get fired, unless he continued doing it. But, since he's a freeper, it's likely he's said/done other things in the past, and that this might put him over the edge and result in justified firing.

Your employer is fortunate to have good employees like you to pick up the slack.