William travelled a lot until it got too much for him. So he loved travel documentaries. All the Michael Palin ones. But as he also loved history, he also loved one called Around the World in 80 Treasures - can't remember the guy's name, although I could have nearly recited it! - it was a box set. And he loved nature and wildlife documentaries too. We had a huge collection of dvds - all the BBC ones. And he really enjoyed James Herriot's All Creatures Great and Small - I got a complete box set of that for him. He loved it, and could understand that.
I also got recordings & dvds of music stars that he loved or would have been familiar with from his youth. John McCormack, who he remembered his grandparents playing, and Frank Patterson, the Irish Tenor. Kept him happily occupied every evening, as long as I sat with him and watched too.