The family finds Frank and assume he's dying.
They leave him and go on with their lives. He ultimately does wake up, but he leaves the house.
Liam goes on a mission to find him.
Frank goes to the church and tries to light the candles. He's sent to the hospital where he slowly starts to die.
The hospital goes through his files to try find an emergency contact.
Kev and V throw a party for the end of times as they prepare to move away to Kentucky.
It is later revealed that Mickey planned an anniversary party for Ian and Mickey.
As everyone parties the night away, Frank slips in and out of consciousness, seeing the rest of the family.
His letter is never read out, but it harkens back to the series premiere when he introduced his family.
Frank dies and goes to heaven as he reads out the letter. He basically told everyone he hates them.
The final scene finds him being cremated and because of the alcohol in his system, the oven blows up.