Kevin came back from the dead in the season finale of "The Leftovers" Season 2 titled "I Live Here Now" and finally reunited with his family.
Though Season 2 ended on a happy note, it is still unclear that why Patti haunted him and whether she will continue to do so in Season 3 also.
Undoubtedly, there is a personal vendetta that Patti's spirit seeks against Kevin and she is dead set on torturing him. Even though Kevin seemingly got rid of her spirit in Season 2, there is a significant possibility that she will again come back and continue haunting him.
Damon Lindelof, creator of the show, has confirmed that Season 3 will end the series. Hence, the Patti's mystery is surely going to be solved in one of the Season 3's episodes. However, the fate of Kevin and Patti in the last season is not yet revealed.
In an interview with HitFix, Lindelof said: "It's a gut instinct. I feel like there's more story, but not much more. And I don't want to drag it out unnecessarily."
Season 2 ended with Kevin being recovered from death and returned back to home. However, an enraged John was waiting for him having identified his hand-print.
Kevin explained that Evie faked her departure after which John shot him. He was plunged back into the land of the non-living, where he was told by a familiar face that he must sing karaoke to get back home, which he hesitantly did.
After another earthquake, Mary recovered, and Nora took her to Matt at the encampment. Meanwhile, Meg and Evie initiated their plan and the Guilty Remnant infiltrated Jarden, leading the way to chaos and destruction by the outsiders.
In need of aid, Kevin made his way through the distraught town, to Erika's clinic, where he encountered John a second time. The two men reflected on their similar plight, and headed for home.
When Kevin opened the front door, Jill, Laurie, Matt, Mary, Nora, Tom and Lily were all present, awaiting his return.