Charlie Geyer began at age 5 and seemed to turn out OK. LOL. (one of my favorite players of all time)
That might be the beauty of our instrument, Collin. As he grows and has larger lung capacity, the airstream will change and his embouchure will adjust and form naturally. Many middle school children go through this with braces and other dental issues and tend to get through it all right. Awwww....I feel bad though. When he's missing those two front teeth and the many others that will form holes in the front row, you're right, he won't be able to play. Awwww......
You know....I bet you some genius dentist will find a way to keep him going.....you watch.
BINGO! I have the answer. Have an "invisiline" (type of invisible braces) mouthguard made and it will simulate having a full set of teeth until they grow in. Of course, there are some design issues to figure out as the teeth lengthen, but the answer hovers around something like that.