I like this time of year (I work part time as a pt and massage therapist) I think its great that people feel inspired to get off their backsides and do something. It doesn't matter what size they are - most of my clients are very overweight and want to improve their health - its not the size and shape that matters, its whats on the inside that counts.
With a little bit of advice and encouragement these people can see fantastic results in a very short space of time, they just need a nudge to take their first steps.
Be patient with them....before you can run you have to learn to walk.
I did the premier pt and sports massage - pt is a bit hit and miss at the moment but working as massage therapist in osteopathy clinic is going well. The premier course is excellent but it is a tough 12 weeks - I'd recommend it.
Haven't dislocated a shoulder (touches some wood!) but you're right in thinking it will never be as strong as it originally was. I would recommend strengthening the rotator cuff muscles and the upper back area. Might be worth speaking to a sports injuries specialist to get a series of exercises to do.