After enduring the loss of his vision and suffering through multiple brain surgeries, both stemming from a life-threatening lung condition called cystic fibrosis, 16-year-old Gideon of Allen, Mich. remains optimistic and brightens everyone else’s lives with his cheery disposition. In fact, his optimism may even be comparable to that of his hero, that “incurable optimist,” Michael J. Fox.

Just two years ago, Gideon was suffering from a severe sinus infection brought about door his cystic fibrosis when things took a turn for the worse; the infection spread to his brain and caused an abcess...