He might start by observing. Aang is a curious person, so he'd likely watch how people live, how they interact with technology. He may also try to find other benders to learn about any new developments in bending. And he'd probably use his kind heart to make friends easily in this new future environment.
Aang might go into a deep state of depression. He has always been an emotional character, and having his heart broken by Katara, someone he loves deeply, could send him into a downward spiral. He might isolate himself from his friends and stop practicing his bending for a while.
Well, Aang being the Avatar has a deep connection with the elements. In this fanfiction, perhaps he enters the Avatar State and uses all his elemental powers in harmony. He could use waterbending to create moisture and cool the volcano, combined with his airbending to disperse the heat and gases.
In the comics, Daredevil's marital status varies. But one notable character he marries is Elektra Natchios. However, the comic universe is complex, and there might be alternate story arcs with different spouses.
Thor's marital partner in the comics is not always consistent. Sometimes it's Jane Foster, and in other cases, it could be someone else. It really depends on the creative direction of the particular comic series.