Luke McMahon wrote a special song for his childhood friend Blair Chapin. They've been friends since preschool, but since Blair was diagnosed with Sanfilippo Syndrome—a progressive cell disease with no known cure—Luke's watched Blair battle and overcome countless medical challenges.

To raise money for lifesaving research on Sanfilippo Syndrome, Luke wrote "I Won't Let Go," an emotional song that takes a whole new meaning once you learn the heartwarming friendship behind it.

Pitch in yourself at Luke's GoFundMe campaign!