As I said at first, he is really talented. His songs touched hearts of people all around the world. If he was not, it would be impossible. When I watch his singing, I get goose bumps saying "such a wonderful singer".
Also he became great singer with his disability. Of course there are many people live with disability but Stevie does not just "live." He "loves" his life and music. Disability couldn't overcome him. He accept his destiny and gave us his precious songs.
Finally he tried to help people in need. For example, he joined in the beautiful song "We are the world." That project was for Ethiopian in 1985 and for Haiti in 2010. He joined in both. Such thing show us his humanism.