X
I’m going to say something different from most, this guy might be genuine, he might just be some kid thats a bit lost. He might be a scammer but we haven’t heard proof of that yet.
HOWEVER, you can not move a stranger, however lovely, in with your teenage son. That’s just not a thing. If he wants to come live with you, AND he can get there by himself, then why can’t he live on the sofa? You also mention your siblings being supportive, why can’t he share with them? Are they younger than you?
Could he even move there legally? Would there be immigration issues if he tried?
See if you can read the messages yourself between the two of them, try to work out who’s suggesting these things. Is he talking about lack of money a lot? Is he constantly having ‘situations’ that your mom needs to fix?