My dad has always had his way. In everything. I'm trying to remember this and understand but at times we have to tell him things and he won't listen . He lives with my husband and me. We've started a schedule of 3hr increments. Works when he wants it to. I'm so stressed, Dr put me on high bp meds. Not trying to whine, just need help with explaining to my dad that he really needs to stay on some kind of schedule for him and me.
And why did you move your dad in with you if you already knew he had to have his own way? Just in general, either you need to develop some serious serenity and acceptance that you can't change him or figure out a way to use his available resources for him to have housing and care elsewhere.
Overall, can you use some of Dad's money to hire a companion for a few hours a few days a week. It will occupy Dad (walks/rides in a wheel chair; playing cards, going to a kids soccer game, etc) and it will give you some down time.
When you moved your dad in with you was it supposed to be temporary? You need to ask yourself whether or not you want your dad living with you permanently. And you definitely need to ask your husband if he wants a roommate.
Also, there are plenty of threads on this forum about a parent living with you. Search for terms like "regret" "guilt" and "marriage" and you will have plenty of food for thought from people who are caring for someone in their homes.
I've come to the conclusion that many seniors just aren't into change. And providing advice, information, and requests, aren't that productive either. That includes seniors who do not have cognitive decline.
I learned to pick my battles. I have very few things that I freak out over. One is my 79 year-old dad climbing on the roof to clean gutters and the other is my 75 year-old mom taking her antidepressant meds. Other than that, I let it go.
For some reason, your dad feels like he wants to do what he wants to do when it wants to do it. And at 85, I may feel that way too. He has little in his control right now. Why not let him set his schedule and if he doesn't want one, what's the problem with that? Why is the schedule so important? Why can't he just relax as he likes?
I wouldn't hold my breath thinking he will change, so if it's a huge stressor for you, I'd explore other options for his care.