I can tell you he is going to be a hard gainer. It's not impossible to put on some weight especially if he can do so in the lower body, but his upper body strength is going to max out pretty low for an offensive linemen.
I see what you mean Austin Bill, and I have to agree with you. But here's hoping he proves us wrong.
Its possible the coaches see something else position wise-- maybe D end or Tight end if he has good hands and a little speed. it wouldn't be the first time a position change from HS to college has turned into gold.