Ok, perhaps I am being harsh. The music therapy scientists have done a great job proving that people feel/ get better when they get to hear tunes that they love. No shit. But the american music therapy association thinks that you need to get certified and study at an approved music therapy program in order to accomplish this task.
I can be a fan of official-ness at times, this is a situation of creating false barriers to rocking someone's socks off. If you know a friend or relative who is sick, go play their favorite songs. Book shows in hospitals. If grandpa used to drum during the swing era, go to his bed side and bang a snare in his face. No license to rock required.