So I found Airi's father bleeding on the ground after he accidentally summoned some high level demons. I wasn't sure exactly when the event was opened up but I did it at 1700. My previous save was 5 hours ago (at 1200) and I'm wondering if I could have saved him if I made it on time.
I haven't played my copy of DS2, but this is the info my google-fu has yielded.
You can maybe save him by not following his events because he presumably doesn't try to summon Jikokuten.
You need him to die in order to save him. If you proceed through all his events, he can be seen alive during the Daichi+ ending. You essentially need to get your team to fate 4, follow the Dera Deka events and choose the restoration ending if I read correctly. You may need to recruit everyone as well when doing so or maybe that's just to see the complete ending for all characters.