My long-time partner and his parents and siblings love each other but have a somewhat conflicted relationship. I have known them for many years now and I still can't put my finger on it. The feeling I get is the children a) do not feel accepted the way they are by their parents and b) tried to draw healthy boundaries with their parents early on but they either failed (the parents wouldn't allow it) or managed to do it but it was at the expense of having a good relationship with their parents.
I will elaborate later about the parents, but for now let's focus on the siblings.
They seem to love each other but they do not APPRECIATE each other, which is a new concept for me, honestly (call me naïve if you will). They are very judgemental of one another all while feeling deeply hurt because their siblings do not accept them the way they are. I have known the whole family for many years now and I haven't seen any significant improvements in the relationships. Months go by without getting a call from one of them to meet for dinner or whatever. My partner is the one who makes more errorts to connect comparatively. They never showed any interest in getting close with me either (I was more than willing while they tried quite hard to avoid me).