Boobs are boobs.
Whether they’re big or small, he will sleep on them like nobody’s business. He won’t even notice the size of them until you say something about them.
And when you do, out of curiosity he’ll compare both your chests with each other and if he finds out his is bigger than yours he’ll be slightly surprised. I could be a female model.
But if yours is bigger he’s like, damn.
Excluding that, there’s nothing else that really happens, he doesn’t bring it up at all because it’s just… boobs, but if you do then he’ll say something to try and comfort you in any way he can.
Or he’ll be agreeing with you in situations where you’re saying they look good in a specific outfit. All to reassure you but it genuinely does look good in the outfit.