Why'd he bother to go through all the trouble to get...?

First of all why do you want to only be FWB when he asked you to be his girlfriend? Does he know you don't want to be his GF and instead only FWB? Secondly, you're right where you started because like you said, his family doesn't want him to date you. I think you should give him space and respect his situation so he doesn't end up getting into problems with his family, and maybe see him in secrecy until he turns 18 and can see whoever he wants to. Good luck.