Not your place to say this.
If it was mud, it got slung at his wife. No ex mentioned.
This may be one of the most obnoxious, arrogant things I have seen from a parent on CC. You are talking about someone who is probably 16. It’s not too late for him to become an awesome anything, except maybe a hockey player or figure skater. (I don’t know of any awesome skaters who started that late.)
You, and many other people, are right to caution against trying to “fix” a stepchild. But you’re wrong to presume that’s the only thing that could be happening here.