Simple answer ... don't.   Let him come around to it on his own.  Bitcoin isn't going away, it isn't a race and there really is no reason for a financial conservative, technologiclaly unsophistication person who sees no need or use for Bitcoin to get "into it".

If you want, the next time you need a gift get him a physical Bitcoin and tell him to keep it safe.  If 5, 10, 30 years from now he realizes that gift you got him is worth a fortune well that might get him into it.  If Bitcoin fails well it didn't really cost him anything except not getting a different gift in the past.