Basically any movement or prolonged pose becomes it’s own exercise.
“wall sit” might not be good for the ankle.
What you can do for your back, are exercises laying on your stomach, and then lifting and moving arms and legs. Up and down, can slow or faster, just holding them up isn’t easy either. You’ll figure out which poses tire and train which muscles. If you do it straight it’s more for those along your spin, if you spread your arms it’s more for the shoulders.
Side leg raises are probably another idea that shouldn’t put strain on your injuries.
The rest kind of depends how much you can even just stand. Maybe something involving Therabands?
Humor is difficult.
It’s tough when it’s actually a bad joke or they are telling it badly, but they find it funny.
If it’s a genuinely funny situation / retelling, both of you laughing about the same thing and also about how the person in question is struggling to breathe because they have to laugh so much, that’s funny.
But it really really really depends.