(view spoiler)[Now that Cath and Ben have access to financial assistance for him, Jem's chances are much better, and he'll have periods of relatively good health, like William. In my mind, Jem and William both survive to be at least middle-aged. It's over-optimistic for the period, but I won't have them die so young, and that's that!
A lot of William's unhappiness isn't his illness itself but the loneliness and frustration it brings. He has the best medical care, and Lucien, McHenry, and Mrs Spence do their best, but he doesn't have enough social and emotional support. Living with a chronic illness isn't easy, even nowadays, but with support and the right people around you it's possible to live a fulfilling and happy life despite it. And in my mind, both Jem and William do, in the end. :) (hide spoiler)]
A lot of William's unhappiness isn't his illness itself but the loneliness and frustration it brings. He has the best medical care, and Lucien, McHenry, and Mrs Spence do their best, but he doesn't have enough social and emotional support. Living with a chronic illness isn't easy, even nowadays, but with support and the right people around you it's possible to live a fulfilling and happy life despite it. And in my mind, both Jem and William do, in the end. :) (hide spoiler)]