Not suggestions necessarily but some anecdotes that might give you some ideas -- one of my friends had knee surgery last year. When he started cycling again he switched out clipless pedals for flat, to reduce the chance of falling if he was unstable. Another friend recovered from a broken femur and found she could ride her bike but had trouble getting a leg over to get on and off. She either needed something to hold onto (such as the side of a car or a fence ) or she would lay the bike down and then step over it. So in both cases small modifications made things easier for them. Also they both started with short easy rides and increased their efforts slowly, and they had friends with them in case they needed any help.

Good luck!!