for what it's worth, the CAA allowed a thalidomide victim who had no fingers worth talking about to do a PPL a number of years ago (late 80's) , he did his training, and some "extra" requirements at Shoreham around the time I was doing a twin rating there.
He was just at the solo stage when I was there, and seemed to be coping well, despite the limitations he had.
I don't know if he continued flying, or if it was just a "prove I can do this" scenario