Alton would try to fill Superman's place after Clark died out of a sense of responsibility. He'd probably meet Kon during this time. He'd hate it though, and throw himself at the Justice League for help. He doesn't want to help anyone when Clark was alive, but now that there's one less Kryptonian he wants to help Kara. He definably is more as a reserve/supports Kara when she needs a break. And that's by choice, he doesn't want the spotlight at all.
Cue @ least one member of the League that don't know Clark personally to go "Wait there's another Kryptonian and he's just been chilling on a cattle ranch this whole time???"
"I don't have to help anyone just because I have powers, asshole"

















