Does this guy like me back?

I think that Javier is an open guy that also sounds outgoing and likes to treat women nicely. He has a girl that he likes however, his ex, since you mentioned that "he still liked his ex". I think that he likes you as a woman who he can treat nicely and respect, but as far as being his girl or girlfriend I don't think you could be those at the moment. I think he likes you back, definitely, but not in the sense of being his number one girlfriend. Your mom probably doesn't approve of him because you are not his number one girlfriend.