I don't think red light is going to penetrate far enough to do anything directly for a rotator cuff, but it might help with the body's overall health, relaxation, and even recovery.
All the red light you need is available free, just dress up fully and lie in the sun!
Especially with age I think a variety of similar treatments may also have many benefits - from sauna and steam room to hot shower or bath.
Of course don't overdo any of them, a few minutes once a day seems about right.