TV highlights 26/04/2012

Louis Theroux: Extreme Love - Dementia 9pm, BBC2 Tonight, Louis is in Phoenix, Arizona, a city known as America's "capital of dementia". He's here to see how relatives cope as their loved ones slip into a "twilight world of half-remembered reality". Selinda, who is just 49 and has Alzheimer's, can't dial the numbers on a phone to make a call, while Nancy, who is cared for at home by her husband, can't remember her own name. There are flourishes of personality, but ultimately the partners must endure the gradual loss of their loved ones with patience and love. Martin Skegg The Plot To Bring Down Britain's Planes 9pm, Channel 4 Documentary detailing the thwarted 2006 terror plot staged by a group of young men from east London who planned to blow up several planes as they left Heathrow using explosives in drinks cans – the reason you can't take liquids on planes any more. We go behind the scenes of the MI5 investigation and hear some of the bickering that went on between UK and US authorities as time ticked away. It's lucky the Feds managed to reach agreement because the attacks, if successful, would have killed up to 2,000 people. Julia Raeside The Kidnap Diaries 9pm, BBC4 Douglas Henshall stars as journalist Sean Langan, who was kidnapped and held hostage by the Taliban when he crossed over into Pakistan ostensibly to film their training camps. Things didn't go according to plan for Langan – not that there was much of a plan to begin with. Still, he was in good company, as the Taliban seem to be governed by random and bizarre rules that are impossible to predict or understand. Even if you know how Langan's story played out, this dramatisation is still a thrilling and strange adventure. Phelim O'Neill Playhouse Presents: Nixon's The One 9pm, Sky Arts 1 "Bob, I've been thinking … I want you to take these tapes and destroy them." As we now know, White House chief of staff Bob Haldeman did not destroy the Nixon tapes in 1973. And here are some high/low lights from the actual transcripts, sublimely acted out by Harry Shearer as Tricky Dicky – not such a stretch from his performances as Mr Burns – which include the paranoid, power-mad president's obsession with his own speeches, and the homophobic admission that "I can't shake hands with anybody from San Francisco". Frighteningly good. Ali Catterall Grandma's House 10pm, BBC2 In the second episode in this new series of Simon Amstell's queasy postmodern sitcom, Simon Amstell, played by Simon Amstell, decides that it might be time for him to move out of his titular accommodation and into something a little more detached from his bickering relatives. Fortunately he may have found a saviour in the form of his Uncle Barry. As ever, Amstell's heavily self-referential script and performance make for a uniquely awkward viewing experience. Ben Arnold Eastbound & Down 10pm, FX Whenever Will Ferrell (who also produces) rocks up as silver-haired car salesman and Kenny Powers nemesis Ashley Schaeffer, things tend to get a whole lot more cartoonish. With so many inveterate scene-stealers and over-actors already in the cast, Ferrell's presence tips the whole thing into a pissing contest. But tonight, broad is perhaps what the show needs. Baby Toby goes missing and a mysterious gang of bikers roll into town. Are Kenny's days as a father over? Will some 80s-movies-inspired street fighting solve everything? PO'N