"Family" is the twenty-first episode of the third season of House, and the sixty-seventh episode overall.
Plot
Wilson prepares a 14-year-old leukemia patient named Nick for a last resort bone-marrow transplant from his younger brother, Matty. However, when his brother sneezes, the team must figure out what is wrong with him before the transplant can occur. With only 5 days left for Nick, the team resorts to worsening Matty's condition to reveal what it is and treat it quickly. While the team wonders between an infection and an autoimmune disease, Matty actually gets seriously sick and starts to bleed out of his ears. Meanwhile, Foreman is busy checking the donor list to provide a riskier but immediate bone marrow donor. House disagrees, saying that Foreman is simply taking the safe route to avoid killing another patient (in light of the events of the previous episode). The first transplant does not work, and Nick is dying. House convinces Nick that if he is going to die, he should die, saving Matty. House proposes that if Matty's bone marrow is transplanted into Nick, whatever Matty has will spread and kill Nick, but will tell the team Matty's condition. The boys' parents originally oppose this, but are convinced by Nick to allow the procedure. Before the transplant begins, the team finds out that the younger brother is suffering from a fungal infection known as histoplasmosis. He developed the fungal infection by playing in the dirt of his new playhouse. Foreman proposes that the site used to have a chickencoop on it and still had the spores in the soil. Foreman decides to take bone marrow from Matty in order to save Nick's life. However, since Matty is too sick to be sedated, Foreman removes his marrow without anesthesia—a process so painful that it's essentially torture in Foreman's eyes. House applauds the decision, while Foreman realizes he is too much like House for his own good, and tells House he is resigning.
Outside the hospital, House must deal with his new dog, Hector, about whom House does not seem to care. Hector makes a mess in the house, including eating some of House's pills and biting off a piece of House's cane. The doctor tries to get rid of the dog by leaving the door of his apartment open, but Hector just stays inside (though somebody does enter and steal House's stereo). At the end of the episode, we learn that Wilson's ex-wife is now able to have dogs at her condo and she can take Hector back if House wants. House scoffs at the idea of keeping the dog but it seems that House and Hector developed a certain fondness for each other. When Wilson calls for Hector, Hector stands up and starts limping towards Wilson. Then Wilson looks at House with an accusing look. House merely says, "Accidents happen," while handing over the leash. Wilson walks out with Hector, followed by House seeing them dramatically leave while the song "Ain't No Reason" by Brett Dennen plays.
Music
When House reveals the recently bought cane, as he exits the elevator the music playing is Highway to Hell by AC/DC
The song playing while Wilson is leaving with Hector is Ain't No Reason by Brett Dennen.
