the bull who became part of the friend group how does that even happen

have a friend in toronto who somehow went from being a bull for one couple to being invited to their kid's birthday parties and bbqs and is now genuinely part of the friend group with them and 3 other couples. like a proper friend, not just the play guy. and im sitting here wondering how do you even cross that line because right now im very much in the "you exist when we want to play" category with all my couples and there's a wall between bull and friend that i don't know how to scale. is it organic only or did he actually do something specific. anyone who's actually made that transition please share