If you want to be in a friends with benefits relationship, then he is the man for you.

He has shown no interest in it being anything more than that. Think he will likely look in your direction after his parents die though, when he needs someone new to support his life of no responsibility.

As far as his relationship with his parents, you really don't know what that is. Since you have never met them, you are basing your view only on what the "forever at home" son has told you. Be interesting to hear their side of the story.