I suggest you find a sight with body workers, massage therapists, physical therapists etc to address this question
As a personal trainer it is not within my scope of practice to massage or manipulate my clients muscles nor to give advice.
I agree with Harris, get it checked out by a doctor to m...
Personal training is so much different than even working with two people
Working one and one allows the trainer to focus 100% on their client and to customize their workout
Training a small group can be effective, but not as personal. There are so many other variables that come into play with a ...
Definitely get medical clearance and communicate with his docs.
I suggest short, sustainable "cardio" even flat surface walking until he adjusts/adapts
Don't push him
I would then focus on core and muscle strength training.