Should I be worried enough to stop ex having children?

[Lmls]

My exBPD/NP looks after D15 and S6 every other weekend. A year and a half after separating he is about to get his own place next month. At present he looks after them just 9-5 at his parents as his girlfriend doesn't want anything to do with them.

A short while ago he emailed me whilst on holiday with children and his parents saying that he was worried he would lose it with children. He also intonated suicide (if anything happens to me know that I love the children, I'll have to just try and carry on get on until I can't bear it anymore, I can't live like this anymore etc etc) and although worried about his child harming OCD thoughts, I was always reassured that these were just OCD thoughts as he had in past.

He was meant to have the children this weekend but has arranged a flight to go on holiday with his girlfriend on Sunday. His parents were due to look after the children for him and I had plans and help arranged to decorate the house.

Yesterday he emailed me that he had arranged to pay for D15 to babysit S6 on Sunday. My D15 has had her own mental health issues over past year and struggles to keep her cool with her brother after an hour or so. I raised my concern, using SET, suggesting that if this was at his parents I could understand that it may help them out.

His response was that he expected D15 to look after S6 at my home and any problem I could deal with. I was then told that his mum was ill and that it wasn't fair for his parents to care for them.

When I raised my concerns with how he dealt with situation and his expectation to allow D15 to care for her younger brother all day, initially she planned to go out of the house it seems, with no discussion with me or any clear adult back up he said not to bother and that his dad would pick up children as initially agreed.

My concern is now that if he had his own place, would he have left D and S there without explaining the situation?

I spoke directly with his dad to check what was actually happening and if they were able to care for children or not and he said that they were always expecting to have the children as agreed.

He also said that they felt it necessary to be around when my ex had the children at their house. When gently questioned why they felt it necessary he quickly backtracked suggesting this wasn't really the case. I am pretty sure that it is. Now I am concerned that it is because they believe my ex is not in a good enough place to parent alone. He is currently seeing psychiatrist and therapist and recently diagnosed depressed, with dependent personality and GAD.

My ex and I had recently discussed co- parenting vs parallell parenting and he said that while he thought it better, he wasn't able to co parent. In a way this was a relief, at least we could agree to parallell parent and reduce conflict. Later he texted saying he didn't want to parent alone and would try to co parent. This latest situation is the first contact since then and since boundaries enforced, all using really good advice on this site.

I really don't know how concerned I should be about his ability to even parallell parent just now. He doesn't seem to understand well what children are safely capable of themselves but now I am also concerned about his current state of mind and being around the children generally. I had previously suggested to him that he, I and his psychotherapist meet to discuss a parenting plan but he refused.

He isn't due to have them after tomorrow for two weeks so I have a little time to work out what to do but have no idea what that should be. In the middle of it is not an easy place to necessary see it clearly.