Very good advice @jonibee .
@DeniseW79482 , stubbornness is one of the hardest thing we as caregivers deal with. Besides what joinibee suggested, I would like to suggest a couple of things. Balance is an important thing to address.
If he/you have a full length mirror, stand in front of it and there are various things to do. This encourages visualizing any deviations. However long depends on ability (don't tire). Stand beside him to support if needed. Doing these things you can also try and make it fun.
Watch the stance to see if he sways. Then correct. Do things like lift a leg (and alternate) for a few seconds to see if balance is off. Then you can work on that. Touch nose with each hand. Lean a bit sideways then back each direction. Different things to visualize and correct. The body to mind connection.
Another thing that can be useful and fun is balance ball. They are larger balls that you sit on to work on balance. Some use these as office chairs. To be safe and more fun, get two. (Or one and just be there for support) You both sit across from each other and help each other balance (and you can keep him safe if need be). This can be fun like helping each other by holding hands and leaning. When balance is good you can play patty cake. 😊 If he is not safe be sure to keep these out of reach to use himself.
I don't know if these will help you/him or not, just thought I would chip in with some ideas. Good luck and thank you for your caring support.