I can thnk of at least 2 of my musical friends who have suffered strokes and come back after a period of time and intensive persistence. The one was a fiddle player, and her stroke affected her left hand. It was perhaps the best form of physiotherapy ever that by her sheer dogged determination she got it all back, as well as being proficient on mandolin and guitar.
The other was an accordionist whose stroke affected his ability to read music: he could see the notes on the page and know what he should play, but the notes just did not come out right. He talked about his brain "being scrambled". Again, sheer determination and persistence paid off, and he is back ro pre-stroke playing level.