Baby talk/faces and helplessness. Cant stand it.

I actually need advice on how to bring it up without being mean… I’m seeing a guy that is great in so many ways but the biggest issue is these annoying small gestures that I think will end up ruining the relationship. For instance, he uses made up words like “shmanks” instead of saying ‘thanks’ and I jokingly bring it up like I wont do it again if you say it like that haha… and it’s not registering for him. He asks my permission if he can have more alcohol, weed, food or whatever like a child. He always raises his eyebrows and bends his bottom lip like he’s begging for something. He actually owns a lot of “toys” like action figures which is fine if it was just a few. He’s mature in other ways, make a good living and fixes stuff on his house. But Jesus, he likes to slip into being a kid a lot and it’s revolting to feel like his mom or that I need to baby him. I don’t want him to feel like he has to change for me, but it’s such a turn off and annoying. Is this a compatibility issue at this point? He doesn’t act like a baby towards his friends…