Depending on his ability. Tai Chi is great.

Absolutely agree. See if you can find him a beginner's class in Tai Chi. Make sure you discuss your father's condition with the instructor first. I would also highly suggest trying to combine this with a course in Qigong (chi kung), which combines breathing, stretching, balance and mental focus. It is really a precursor to doing Tai Chi. Your father can do the routines on his own everyday. I do Tai Chi four times a week now and Qigong most days for the past two years. My balance is much better now than it was two years ago. Basically, it's probably as good as anyone else in the class that's over 50.

If he does decide to do it, let me warn you in advance that the forms (basic moves) can be very frustrating at first. This is true for healthy people and more so for PwP. However, I promise your that the people who stick with it "get it" with time. The most important thing is to do it, and then practice a few times a week. My instructor tells me over and over that just doing the routines as much as possible is more important than worrying over getting the moves perfectly correct. With that approach, without realizing, you get it correct over time.

Good luck,

Gary