Thank you, Iz, Green, Lighter. It is a little punch but I truly am pleased that I haven't fallen to bits or had a huge reaction to it. It's been a few days now as well so there's been time for a delayed reaction to kick in! I think it's a good sign.
One thing I have thought about is the degree of control she needs to have. In the card she has written what she wants do and has given me two options in response to it. There's still no space for me in it. She can't/won't get in touch and say "I'd like to sort this out. How do you feel, what do you want, what can I do to change this situation?" Because of course that would mean she isn't in control of it. So she makes her offer - cash on a regular basis - and then gives instructions of how to respond yes or no. She also mentions that she puts money away for him and will carry on doing so. It seems to be all she can think of - money, money, money.
I did think about writing to her, explaining how much damage she's done to him, confronting her with a list of all the lies she's told, all the medical issues that have been fudged or misdiagnosed because she kept giving people the wrong information, stating, again, that her husband sexually abused me, as well as having goodness only knows how many affairs and treating everyone like shit. I did think about saying 'Meet with me, I want to tell you to your face'. And I thought about making it clear that it's actually my son that doesn't want to see her, not me stopping him from doing so (although I have to say if he ever did want to see her there's no way I'd allow it unsupervised but that's a whole other issue) and that he'll never be able to manage his own money because of his learning difficulties, so unless we are so skint there's no alternative but to accept it from her, the money she's planning to give him when he turns 18 will be going to charity (and preferably one that offers counselling to domestic abuse survivors or something similar). So I did think about all of that. But there is, as you all know, absolutely no point and all I'll be doing is opening the door again and I don't want to do that.
So my boundary gate is staying firmly closed! I've got this place to let off a little steam if I need to (thank you, Dr G!), I'm moving forward with plans for myself and my boy to make our lives easier and more enjoyable, I'm trying to eat better and get more exercise and my mum is staying in the past where she needs to be.