Johnny smiles before he dies because?

Johnny doesn't smile before he dies..... his eyes, however, glowed because Dally was proud of him.

Johnny stirred weakly, then opened his eyes. "Hey," he managed softly.
"We won," Dally panted. "We beat the Socs. We stomped them--- chased them outa our territory."
Johnny didn't even try to grin at him. "Useless... fighting's no good...." He was awful white.
Dally licked his lips nervously. "They're still writing editorials about you in the paper. For being a hero and all." He was talking too fast and too calmly. "Yeah, they're calling you a hero now and heroizin' all the greasers. We're all proud of you, buddy."
Johnny's eyes glowed. Dally was proud of him. That was all Johnny had ever wanted.
"Ponyboy."
I barely heard him. I came closer and leaned over to hear what he was going to say.
"Stay gold, Ponyboy. Stay gold..." The pillow seemed to sink a little, and Johnny died.