This will be long and I have NC'd due to this being very personal.
For background I am mid-30s and brother is 30. I have been no contact with my brother since as soon as was possible, DM knows this. I get on well with my DM and often spend time on lunches, visiting events and so on with her.
The main problem is that even though I've made clear I want nothing to do with him, I can't get away from his behaviour impacting me due to his toxic relationship with my DM.
For example - last Christmas I had plans for the day with DM but less than a week to go and he again got chucked out by his GF and was staying at DMs so I couldn't go and spent it alone with no food. Another example - I looked after DMs cat whilst on holiday, had to deal with baliffs at her door. It just brings back all the anxious and unpleasant feelings, plus it's horrible being dumped in preference for someone else's lastest drama.
My DM seems to constantly gaslight me about having a problem with this, insinuating I'm saying she should chuck him out, or that she is still his parent etc. I really don't care what she does with him, I'm beyond trying to help her, but I just don't want to have anything to do with him or be impacted by his terrible life choices.
I'm really looking for experiences and thoughts on this. I feel like she will never realise that she is enabling him, that it impacts her other relationships but also is it really something to lose your relationship with your mother over? That said, it is so stressful not being able to trust plans you've made, and being hurt by all of it.
More info:
The reason I am NC with B is that since his early teenage years he has been an incredibly unpleasant person. He was/is violent, verbally abusive, stole from me/us, took drugs, regularly got arrested, kept dangerous company that knew where we lived and so on. It was a really stressful time for me as I was doing exams, was so anxious about what was happening at home and my DM was also an alcoholic which was really bad at the time.
He is NT but does have some medical issues which adds to DM case of her need to 'support' him. He also financially abuses my DM, and she just allows him to.
I've tried helping her see how toxic this is, and she does acknowledge it, but she's always been quite a meek and mild person and has never really parented so I don't think she has the strength or skills to manage the situation. It is easier for her to acquiesce to him. I accept I can't change this and it will only be her who can make things change.