What did the person you got him from say about his breed?
Sometimes lopped eared rabbits ears don't lop right away. But maybe he's not really a Holland or is a mix? His ear shape/size doesn't really look like typical Holland lop ears to me. I'm not an expert though.
Give it some time. He's still young, and I think there's still a chance his ears could lop if he is really a lop rabbit. If not, luckily the care for rabbits is the same really no matter what the breed is. He's adorable, no matter what breed!
If he's not a lop, I think you'll probably have more luck guessing at his breed once he's fully grown. He very well could just be some kind of mix as well.