I mentioned it in a friendly way after the meeting at the school recently (24 October) to see "if it would help" but she said she found it harder that way round, but I think "harder" in this sense is more that she misses him.
I am not sure I want to just reverse the situation - I would want to ensure that he spent the majority of his time with me so that I can reduce any negative influence as much as possible. My thinking at the moment is that he is with me continuously with her seeing him once every other weekend. Over night I would be reluctant - she has told be she has medication which she takes at night which "wipes her out" for a few hours, and I'm concerned about her ability to manage his diabetes should something go wrong, which it does, albeit rarely.
Yes, several times. He has been known to social services for many years, and I'm not sure of every involvement as much of it was done directly with his mother. However, last year when she took an overdose social services were contacted by the hospital who then contacted me. Shortly after was the drunken incident when I contacted them, and that started the process of a child protection investigation. The conclusion of that was that he was not in danger but they recommended he live with me during the week and that we went through a Family Group Conference. The Conference was of little benefit - there were some short lived improvements. To date social services have been primarily interested in getting her the help she needs to parent more effectively but over the long term this doesn't appear to be improving. If anything I would say his behaviour, as reported by her, is deteriorating. I'm not prepared to sit by and watch his behaviour continue to go unmanaged any more hence wanting to take direct action.
I have tried contacting social services in the last few days as the BPD diagnosis is new (new information to me at least) and reinforces my view.