Yeah if he's for certain NOT MS13 or anything else/no criminal record, and is legal in the US, then yeah he should be allowed to come back.
But let's be honest, he's at least close enough to MS13 that he was hanging out with them, so I'm skeptical he's they type of person we want raising the next generation of American children (even as "Maryland father.") Was he counseling MS-13 gang members on leaving the gang life behind? Maybe he was a pastor/priest working to show them a better way to live? That's a different story too. I doubt it's the latter.
"Choose who you hang out with wisely, or you run the risk of guilt by association."
-Mama
Mama's smart.