Perhaps we should let it go, MMM.
I agree with you that this is a train wreck waiting to happen. None of the pieces seem to be in place and it's only a matter of time before something gives.
However, love is definitely blind and when you throw in the raging hormones of a teenager along with their feeling of invincibility, I'm sure that any logical suggestion we give him will bounce off like water off a duck's back.
He'll probably learn the hard way and who knows? In ten years, he may even return to this forum to dissuade the next teen who decides to follow in his footsteps. Of course his pleas will go unaffected but such is life... Some of us have to learn the hard way.
If Sephiroth was my son, I'd rip him a new hole but luckily for him, he isn't... even though he's young enough to be.