My God @ToWeeornotToWee I have just read all of your posts, and the responses since your last post. I know that you are not, but I really want you to be a troll, and for this to be all made up.
I really feel like this is gross abuse from your ex (and his new partner?), as I had something sort of similar with my youngest child and her Dad and his new partner. Many years ago now, both my ex and his new partner were fine at being a DDad and DSM, maybe even good or very good at it in every other way, but what they did about a connected toilet issue with my youngest (a toddler at the time) meant that my DD ended up in hospital for 5 days, and under the care of a consultant paediatrician for several years (the problem was not fully resolved until about year 3 in school years).
My ex and his new partner, and my newish partner, were for a while under a query - not as strong as a suspicion - of sexual abuse. I don't think that I can have been a concern to SSs or the Paediatrician for very long - if at all - as only a nurse or me were allowed to give an intimate treatment to my child for the resulting ongoing problem. When our youngest was visiting her DDad they had to get a nurse in to perform the procedure. Anyway, thank God, sexual abuse was not found to be the issue, the cause of the problem was much less than that, but did include what these days would be considered the use of an action/behaviour which is considered (and I have always been against it) very bad in England, and I think is now illegal in Scotland and Wales. My child was also found to be ND, but that was quite a lot later - was one condition at least part of the cause of the other, I don't know. I am really sorry if this paragraph has been too confusing, but I think that one of the other parties is on Mumsnet, so have had to be careful about what I have said, or it could be too outing!
Anyway, back to you and your poor DCren OP, I think that the potential for long-term harm being caused to your children is far too high, and personally I really want your ex to lose his trusted work position if it has anything - as you imply it does - to do with any child's welfare. I wish that I could send you extra strength to deal with him on both the personal level that is affecting your DCren, and on a wider level that will lead to him losing any position of trust when dealing with children through his job. I am horrified (as you must be) about him being able to make any decisions affecting your own, or anyone else's children. You and your DC have all my sympathy, and I wish you all the very best of luck - not that you should need luck - in the near and far future. ❤️