The Quest of Carth and his Son

[Arzadon]

To clarify, I have already reached the maximum of my relationship with Carth, I mean I have already reached the part where he talks about his dead wife and his son, a question that right now I am in the middle of the story of Korriban (I left Korriban as the last planet) but Dustil's quest does not activate, I spent more than 1 hour investigating and traveling from planet to planet with Carth in the party and nothing. (And if you already completed Leviathan).

[Dethlane]

IIRC it doesn't trigger after the Leviathan skirmish. You can try to use save editor to add this quest to your journal.