In "Holding On" Wilson's fate is revealed quickly to its audience.
His cancer is not going away and he's refusing further treatment and instead opting to live out his last five or six months without being sick from chemotherapy. House is much less willing to accept Wilson's choice and acts out at the hospital by taking Foreman's offer of friendship and turning that into a full-on hospital flooding.
While House and Wilson grapple with Wilson's choice and House tries desperately to change Wilson's mind, the patient of the week, Derrick, comes in with a nose bleed, but House's team soon finds out he is hearing his dead brother's voice in his head. Wilson continues to deal with his impending death by contacting Thirteen and discussing their similar situations. Thirteen is honest with him and encourages Wilson to try the chemotherapy and see how he feels after a month or a two of treatment. She then goes to House and they discuss House's willingness to let Thirteen live out her life the way she wanted to even though House's team would suffer. Calling her firing "the most selfless thing anyone has ever done for me" Thirteen gives House something to think about.
As far as the patient goes, House diagnoses him before the end of the episode, but the patient's unwillingness to give up his brother's voice takes a dangerous turn as he attempts suicide. House reacts by choking the patient and forcing him to fight for his life. Park only stops House by hitting him on the back of his head with his own cane.
By the end of the episode, House and Wilson reconcile and House accepts Wilson's choice to not accept treatment. They begin planning how they'd like the spend Wilson's last days when the hospital lawyer comes in and tells House that his flooding of the hospital was in breech of his parole and he needs to finish out the rest of his prison sentence. House must leave and go back to prison for 6 months, the exact amount of time Wilson has left.