Thanks for the replies. Honestly, I'm perfectly fine with him not being allowed back however, I know he will just try to re-enter illegally again.
He claims that the gangs in El Salvador were threatening him and that is why his life is in danger. He's lost several friends down there. Apparently they aren't too nice with deportees.
My only reason for wanting him to be legal here is for child support purposes. Again, thank you for the responses.

