im confused what was toby talking about when...Spoiler

I have been thinking of that, too. I think it can be that Toby means that Jonathan isn't "really" sick - just depressed - and that he can do great things in his life. Toby himself is out of help and this is his way to tell Jonathan that there's hope for him. It's a good bye, really. Toby letting Jonathan know he's going but that Jonathan will stay and live a great life. Well, that's what I think.

But I don't think Toby clearly decided to make his final choice until he sees Jonathan and Rachel dancing, underscoring that he's never going to have the girl he wants, perhaps symbolizing that Jonathan will make it in life while he, in his own perception, never can. That scene always pokes at me because it starts off so frivolous but there's really a lot there. Even the way it ends, with Toby dancing with someone else for a second as he moves into the kitchen, then shifting into a darker mode, obviously messed up from the intimacy he's just seen.