A parent with a mental illness is still a parent. If the person is in treatment and is stable, they should be able to see their children. Instead, we have a damaged court system that takes custody away and is some cases only allows for supervised visitation.
As a patient I have to often white knuckle it so I will not need to go inpatient. If I go inpatient, I need letters from doctors and a meeting with a separate psychologist just to see my kids again.
Thankfully, all of my kids will be 18 within the next 6 years. At that point it will matter what they think and how they feel about seeing me. There will not be a visitation schedule or a holiday schedule. I hope that the kids will still want me as part of their lives. That is to be seen.
The other aspect of being a non-custodial parent is that it is public record. Any parent can look up and see that big black dot and not want me around their children. No one ever did an assessment of my competence to take care of my kids. They just assumed that I would not be able too. I think my kids are the ones who have been hurt the most.