I'm at a loss

This will be long winded, I'm apologize. You need a little back story to kinda get what's going on. I am 35, I have adhd . In my 20s I went through a really rough time and was diagnosed with all kinds of issues. At 32 my mom tells me she was told I had adhd when I was 8, but did nothing about it. My adhd was what was causing all of my issues in my 20s. I finally started treating my adhd which unfortunately caused my anxiety and ocd to spike through the roof.

I have 4 kids who are all nerospicy as well, 15f ADHD and anxiety, 13f ASD, anxiety and ADHD, 8m CADHD and I suspect ASD or ODD and 5m ADHD. MY 15F refuses to acknowledge or treat her adhd and I see her going down the path I went and I'm worried for her. My 8m is the hardest of the bunch with emotional disregulation, anger issues, impulse control problems, you name it he's got it. We still haven't got his meds straight, they either cause him to lose weight, which he can't afford to do cause his already skin and bones, or they don't work. He is in therapy. My 5yo seems to have anger issues and emotional disregulation.

Now I have done a TON of work to better myself, so I can better parent my kids, I have read all the books, done the research , talked to doctors and school and specialists and therapists, trying to make my kids life and my life easier. Teach them how to cope and learn about adhd (honestly I should be licensed by now lol ) but nothing seems to help my 8 and 5 yo. I feel like I'm failing. They can't do basic things kids their age should do, my 8yo can't shower without help, they can't put their plates in the sink , if I ask them to do any task, it's a melt down. My 5yo can't dress without help. I can't figure out what I'm doing wrong.

I am , as my un says, a married single mom. Dad is gone 4 days a week, when he is home all he does is yell at them, has no patience for them , and sets expectations of them way to high. So I'm constantly playing referee between them. He says he has adhd, but has no desire to help himself, and doesn't seem to understand any of us. So I'm going this journey alone.

I'm frustrated, overwhelmed, and just feeling like failure cause I can't help my kids. Any advice, please