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.
I don't know much about the physical bitcoins but just did a search. Are the Casascius ones what you're talking about? That was the first thing that came up.
Yes. They make good gifts. I wouldn't try to do anything beyond that. For many people they simply aren't going to be comfortable with the idea of Bitcoin until it has been around for DECADES. Not months or even years but decades. If Bitcoin is still around there is a good chance your Dad will own some in 2033.