LG: just one more point. People sometimes do change and do Teshuvah. Hopefully he will repent one day. If you disrespect him now it may haunt you later when you’ll want to make peace with him.
For now you want to make him see the beauty in Yiddishkeit and Hashem – whose traits and Mitzvos you are glorifying with your positive behavior and derech eretz. Even, or maybe more so if he doesn’t believe at this point.
Much hatzlachah!