Thank you for the replies 😀
Spoke with dp about it and he just won't budge on anything. Says if his mum shares photos how is it different to my step brother and sister sharing it... To me it's different because my step brother or step sister are actually involved in his life! His 'mother' isn't involved one bit. Ahhhh! I wish I could work out a way to explain it to him so he could understand. All he has said is that he can't see a problem. He thinks that we make her feel uncomfortable and that is why she won't speak to us about DS. All because he snapped at her about her drinking.
I'm so over the conversation with him. Just going to ignore it. Never complain again because I guess he doesn't want to try and understand my problems with her.