There are places that have “memory” sections where both parents can live, even if one is not impaired. They don’t have to be separated. There are lots of places that have a “memory” unit where the impaired person would live separately,, but under the same roof. But you may have to pay double or at least discounted for the second unit.
Another option is to add more care/help. You can (for a charge obviously) add a full time nurse to help care, or add more help. I think this depends on the assisted living space, but worth looking into.
Often when someone’s memory goes it brings up a whole host of issues that you can’t conceive of now, making it extremely difficult to manage that person. If your parents are in an assisted living facility that has a memory care unit, it might end up being the best solution for both parents. I know you don’t want to hear that now.
I have a relative that is living in a memory care unit and I see the spouses coming and going all the time. Often the couple will spend their day together in the memory care unit so they have the care needed available to them, but the spouse does not have to take part in the personal care or other things that are difficult. They can just be the spouse and share the time together.
This is a difficult time and I’m sorry you or any of us have to go through it. Don’t hesitate to reach out to the families of people living in these accommodations. Most of us are happy to share experiences and tips for navigating through this difficult situation.