House returns to work and asks for a differential diagnosis on fibrous tissue growth in the heart. Cameron comes up with an autoimmune disorder, which pleases Wilson greatly, as it would mean Matty's bone marrow was healthy and donatable. You know who probably won't be as pleased? Matty. But no one cares about him. House starts giving orders to test the most likely autoimmune disorders until Foreman interrupts, saying he doesn't think they should rule out an infection just yet. House doesn't want to deal with that, because an autoimmune disorder would mean a good outcome for Nick. Foreman finds it hard to believe that the family has one son with cancer and another with an autoimmune disorder. House says that "it sucks for them" is not a good argument. Foreman wants to check out a close match he found in the bone marrow registry. It's not an exact match like Matty is, but Foreman thinks it'll be close enough. House doesn't want to risk giving precious Nick graft-versus-host disease, and he overrules Foreman and tells the Cottages to go look for an autoimmune disease.
Cameron goes to work taking blood from Matty to test, and Matty sure is looking healthy after having an open-heart procedure done. She tells the parents, who are starting to lose faith in PPTH (finally), that the tests will only take a few hours to do. Meanwhile, Nick has bruises all over his arms.
House and Wilson make their way out of PPTH. House invites Wilson out to the movies, but Wilson is more concerned with his suspicions that Hector's overdose wasn't accidental. House denies this, and karma bites him in the ass when his cane snaps and he falls on the floor. Wilson delightedly says that it wasn't his fault this time, and House says it's the dog's. He chews everything, and House thinks he's had a "good, long life" and it's his time to go. That seems to be the way Matty's parents feel about Matty, too. Cameron's House-is-hurt-alert has gone off, and she rushes to the scene and asks if he's okay. House says that he tripped over Wilson's self-righteousness as Chase offers him a hand up, which he refuses to take. Why does Chase even try anymore? Cameron reports that the autoimmune tests were negative, and Nick's capillaries are starting to leak blood. If that happens in his brain, he'll die. Cameron thinks it's time to check out the close match Foreman found. House still refuses.