The glowing stopped; the old man vanished in a swirl of smoke. When it cleared, there was only Aang. His eyes rolled back; he stumbled and collapsed.
Sokka and Katara ran for him, each grabbing an arm and helping him to his feet. Aang blinked, eyes glowing red in the firelight.
"We got your back," Sokka assured him, resting a hand on it, feeling more than ever that he needed to protect Aang – even if he didn't need protecting.
Instead of protesting, though, Aang looked up and met Sokka's eyes, his face crumpling a little in relief.
"Thanks," he said.
This is at the end of the episode, right after Avatar Roku leaves Aang's body, in case you couldn't tell!