You're getting older and to a point in adult life where you're going to learn you don't want to be associated with people like this. She's shown some selfish behavior and prioritizing herself over her child's well being. I'd question how much the child, now about 8(?), lacks as a sacrifice to his mothers needs.

Show me your 3 closest friends and I'll show you what kind of person you are. I ended a few friendships over this concept because I didn't want to be associated with narcissistic behaviors and general selfishness. Your child comes first- always.