This is a really interesting question!!
It's really hard to imagine not being able to draw anymore. I've spent most of my life drawing and its been a point of stability I couldn't find in any other facet of my life or identity-- it really is the thing that has made me Me for a very long time. But if it weren't something I had the ability to do any more, or had to start over, I'm not sure I'd pick it back up. I'd probably continue down another creative path, for sure, but starting over with something so time consuming sounds daunting. (I'm 25 now, and I've been actively trying to learn/get better at art since around 13. I'm mostly self taught lmao)
I once worked with a woman who had a stroke in her late twenties; she was about to get a degree in English and become a teacher, but after the stroke she lost all her education as well as a significant portion of her memory from the time. She could no longer spell easy words and had to relearn everything-- though she technically had enough credit for the degree there was no way she could teach. This is the closest situation to the one in question that I have seen in real life, and while she did not pick back up with school to pursue teaching she did still lead a happy life, as far as I know, just down a different path.
I'd probably move to photography/films if I couldn't draw anymore, rather than try to start over. I'd definitely still write.