I have Multiple Sclerosis and I have found horseback riding to be the best physical therapy for my MS. I didn't do therapeutic riding as I already rode, but took private hunt seat lessons really emphasising position. Because of my riding I got out of using an electric wheelchair and now just walk with 2 canes.
Just recently, after around 5 years of lessons, I am finally getting my back straight. Everything takes me so long, but I preservere and even as my MS slowly gets worse I can still walk better than I could when I re-started riding.