Do you have any suggestions as to what type of exercises are best for a person who is healing from a bad slip and fall accident when they’re still suffering spasmodically in their legs and mid-upper body?

I would think if you are injured spasmodically in your legs and mid-upper body, you could do sit-ups because it only requires the abdominal system, which is lower/middle in the torso. Legs means you may not be able to do it right, but you can still try to.

I’m not a doctor, maybe your PT could suggest stretches and exercises. My suggestion would be stretches, then maybe into yoga.