I am at a loss for action with a man who refuses to admit he has MS for the last 20 years. I assume this is the reason you broke up. Your daughters health and life is the most important. Your priority is to keep her safe. I would not let your daughter ride with him, even if he drives wherever he wants to go. It is too dangerous.
My personal example. My wife had PPMS. In 1999, she was driving our SUV and came up to an intersection, not a roundabout. She had the stop sign with cars approaching from the right and left. She pushed on the brake as much as she could, but she continued into the intersection. I turned off the key on our vehicle, but it was already in the intersection. Both cars slowed and then stopped, as I jumped out, put my arms up in a stop reaction. Fortunately, these two drivers stopped and patiently waited as I helped her move from the driver’s seat, then walked her to the passenger side, and helped her in the vehicle. With no one behind us, I backed the car out of the street. I waved a “thank you”. They returned my “thanks” and slowly continued on their way. Fortunately, the other drivers were not speeding or we may have been killed. We sat there for a moment and gathered our senses. She quietly said, “I guess this is the end of my driving”. I said, “I think so; I am sorry Doll”. (That was one of my affectionate names for her.) She took it like a woman. Almost, but not crying. I kept saying, “I am sorry” because I knew what another mobility loss meant to her. This was 1999. She passed away in June 2018.
As I said, your daughter’s safety is the most important thing.
If you can’t talk some sense in to him, turn him in to the authorities. Anonymously, if you have two.
He will need a carer in time. The 20-year mark is a turning point for many people. If you could reconcile, do so if he promises not to drive. This would allow him more time with his daughter, and you would not have any daycare, depending upon your daughter’s age. If you have to leave later, you know you have done everything you can and your heart will be clear.
I have extensive nerve damage, and I can’t believe what I did to help my wife. Her three son’s were useless, and I had all of her care, including Home Hospice, until it was time for her to go in full time but with all of my disabilities, I still wonder if I could have done more. Our doctor say, “No”.
Good luck, and may all of you be blessed.