We all need positive reasons to be observant. Fear of hell doesn’t cut it. Neither does “not letting Hitler win.” Today about the only positive reason you’ll hear is the joy of Gemara study.
So it depends on what he values in life. Does he naturally believe in integrity. Show him the many parts of Torah that also do. Does he believe in chesed? Same with compassion. R’ Hirsch has many quotes dealing with protection of the innocent. See Horeb for that. Show him some of those.
What many people in power try to do is shut off the brain and say value what I value or what the community seems to value. However, you can do the opposite and say what do you value. See – the Torah agrees with you.
Then the Torah becomes your friend and your comfort rather than this ball and chain.