If you've watched the music video, the child is alone in a room by himself. If you listen carefully at the beginning of the song, you'll hear Tate saying, "Don't worry Daron (or Danny), they'll never find the gun." Then you hear another voice saying, "Don't be scared." This is apparently the voice of someone who has entered the house, such as a robber. After the child sings, "No one home to catch me..." you hear a "gunshot" as the robber shoots the kid. As a result, he is bound in a wheelchair and is trying to be the best he can and walk again.
If you've watched the music video, the child is alone in a room by himself. If you listen carefully at the beginning of the song, you'll hear Tate saying, "Don't worry Daron (or Danny), they'll never find the gun." Then you hear another voice saying, "Don't be scared." This is apparently the voice of someone who has entered the house, such as a robber. After the child sings, "No one home to catch me..." you hear a "gunshot" as the robber shoots the kid. As a result, he is bound in a wheelchair and is trying to be the best he can and walk again.