Wow girl - that’s awful. And it makes me feel like he only sends you money so he can hold onto that thread of connection to you and vent to you.
Is the money enough to make it worth listening to him? Or should you just become the gray rock, say thanks for the check and respond to nothing else?
I find that as my kids have gotten older, for two of them, understanding their father in the context of narcissism has helped them. This is stressing you in part because it’s making you feel like you have to get in the middle and defend S, but really, maybe the best answer to your ex (and D) would be something along the lines of “well, that’s between you and S”.
Weirdly, I had a dream last night (I never remember my dreams) that had something to do with middle son asking his dad to help repair his computer and him refusing . S’s computer, which he needs for work, IS having a problem with the screen and needs to be fixed but it turns out it should only cost $100 to replace the screen with his AppleCare . The main point of the dream was the pain it causes S when ex selfishly won’t help.