My front teeth were ok but this happened with my molars, my dentist took all my milk molars and a few of my adult molars (4 i think, out of my jaw, to make room in my mouth) out under local anaesthetic and i never needed braces. I'd take him along to the dentist and see what they suggest. The might want to remove the milk tooth purely to give him room to brush the adult one properly, which will be hard if they grow against one another.

Congratulations! It's a huge milestone for you both!

Bx