As you do your complete assessment, I would be looking at the way the client maneuvers and how the client is responding to you in general. You want to be very thorough and ask frank questions so that you can design a realistic and accommodating program.
I would also survey the studio, gym, home, that you will be training in and make sure it is conducive to this client and that you have wheel chair access if that’s the case.
Also, if this is a new found injury I would discuss all physical endeavors with their doctor first.
Also there are organizations such as ACSM offering certifications for Special Populations.