Welcome to you too! Well, I haven't been on here for a long time, but after reading your post I just wanna give you a big ((hug))!!
How about asking your mum why she feels she can associate with your sis and not you firstly. Cos until you actually ask you won't know why she feels this is okay.
If she wants to go by the orgs PROPER way of thinking then it should go like this:
If your sis lives there then she can live with her but not seek out association with her. She can talk to the boyfriend as he is unbaptised but she cannot have him living in the house with your sis as she is condoning their fornication (!!). She cannot talk to you if you are disfellowshiped or you have disassociated yourself. She CAN associate with your girlfreind as she is neither baptised nor disfellowshipped. In fact she SHOULD speak to her. She can obviously see the children linked to your sis.... and any you have!!!
How f**d up is all that!! And the absolute way to make a complete disfunctional family if ever I saw it!! The poor children have NO idea what the heck is going on!!
Not wanting to take over your thread but just to say, my BIL is just like your mum. I called him up to ask why he wouldn't come to my mums when we were there. I am not d'fd but fallen away, live with bfriend etc. His reasoning: He can go to the house if just my boyfriend and kids are there.... but not me. His kids can see mine, but NOT me! There poor little faces as I turned up (they were living next door to my mum) and outside their house when I arrived to see mum! They looked horrified to see me and ran indoors quick! Yep I checked the mirror but I hadn't turned into a monster!! imo! lol. The kids also asked my mum who is fallen away if she is gonna die at armageddon!!! that is the picture they have in their minds!!! NICE and christian I don't think.
Best of luck with your mum, all I can say is this is a great place to come and visit and get advice. It will keep you strong and the people are all so kind and helpful and I have been very happy to belong here!! xxx