Investing for an infant’s future

I’m going to be an auntie! As I will never have kids myself, I’d like to set something aside right now upon my nephew’s birth to start getting him set up for the future. I DON’T want to do an educational savings account, as there’s no way to tell if he’ll ever want to attend college. Is there a good vehicle for savings that will grow reasonably that I can start saving in now for his future, in his name? Or do I just open a new investment account with him as my beneficiary, and then turn it over to him upon his majority? If that’s too complicated, I could absolutely trust my brother to open a joint account on the understanding that it goes to his son. Your suggestions are appreciated!