With his cervical and lumbar fusions he really shouldn't be doing anything over head to begin with. I'm older then him with cervical and lumbar injuries and have no muscle wasting. I've also avoided surgery by working out in ways to avoid further damage and to strengthen spinal support muscle groups.
He literally broke his last lumbar fusion screw doing things he shouldn't have been doing.
I have 3 damaged discs in my spine, L4/L5 and thoracic disc
I work around them , I manage to maintain a pretty decent year round look and remain relatively injury free, in fact I have only tweaked my back once in the gym in the last 5 years , I have had several twinges resulting in spasms from doing general household stuff.
I don't do any exercises bending over and all my dumbbell work for delts and arms is done seated.