He spends the first month after he died trying his best to avoid the demons.
He doesn't know yet why they don't seem to be doing anything with him; he knows his soul is forfeit, the theologians he spent years studying were quite clear on that point, but he'd expected that to involve some amount of being forced into unpleasant situations.
Then again, demons presumably aren't stupid, they've convinced the world that it's possible to summon a demon safely so long as you use a good binding and don't give up your soul. They're probably trying to trick him, convince him that it's safe -- to what end? Even if they're telling the truth and he can take summons, no one will let him talk. But there are billions of them, and some of those billions are smarter than he is, and he doesn't want to underestimate them.
On the third day after his death, he finally tests whether he can make things. He can. He makes himself some food, and some tea, and then he's curious so he makes himself a copy of his apartment the day before his death, and an art project from when he was ten that his mother had accidentally thrown out, and all non-chiplocked writing from the past three days referencing his name, and three different lost libraries.
(Someone comes to complain that the libraries are blocking their view. He makes himself a car and drives until there's no one nearby to complain.)
On the thirty-forth day after his death, he finally makes himself try to take summons. He doesn't want to -- this seems like the sort of thing that would cause the demons to do something with that soul he forfeited -- but there are people summoning demons every day. There's almost no chance that anyone will let him talk, but even a slim chance of preventing anyone else from doing what he did is worth it in expectation.
He takes a summons.
The first thing he notices is that there isn't a binding.
The second thing he notices is that the location is totally unfamiliar and multiple centuries out of date.
"Where am I?" he asks, and then "anyone who summons a demon forfeits their soul it happened to me you have to warn people -- and it's incredibly dangerous to summon a demon unbound -- who are you?"