Apart from the ADHD, it sounds like it’s time for T to get a lawyer who specializes in child custody issues, and preferably a lawyer who is not afraid to go to court. My wife’s first lawyer presented himself as someone who wanted to work hard to avoid court and resolve things through negotiations that reached a mutually acceptable solution. That’s all well and good if everyone’s trying to work towards a good solution, but her ex-husband was ready to burn it all down because she dared to leave him and that first lawyer was almost a liability in the courtroom even with things that should’ve clearly gone her way. Her new lawyer is a fighter and is able to shut down any crap the ex-husband tries to pull now, and he hasn’t tried anything in a couple years.
Unfortunately, a lawyer like that doesn’t come cheap. You can help lower costs some by trying to do as much as you can gathering and organizing evidence so when you meet with the attorney they don’t have to spend as much time doing that. Most of the evidence gathering falls on the client anyway. The attorney should be able to give guidance on what that evidence should be and how to organize it. You’ll probably want at least 3 copies of everything and have it in binders when going to court or some other meeting that needs evidence. And evidence is key with all of this; he can’t just say the kids were with their mom when they missed school, he’ll need to have papers showing the custody schedule and papers showing their attendance.
All of this sounds like it will be a challenge for T, both financially and organizationally. He will have to find a way for the sake of his girls, and will probably need as much help as you and your family can give him. If the ex-wife is trying to prevent the girls from getting treated for their ADHD that could have bad effects for the girls both short- and long-term. Courts and social services generally take a negative view on obstructing treatment, but T will have to prove that’s happening. And it sounds like the mom has tried to weaponize social services against him. He can succeed in fighting against it but will need to do a lot of work.
This might become the most important fight of his life.