I didn't see the Chuck betrayal coming at all. I think in wrestling they call that a 'heel turn', but it made you remember one of the flashbacks where he had to get Jimmy out of jail and he was, 'oh god, not this again', so they have only got closer since the illness. At first I didn't like it, but it's quite easy to imagine being in Chuck's place and not wanting your fuck-up of a brother getting in the way - when you have spent so long building up your reputation, only to have your shifty brother ruining it. You tend to think of the younger sibling having issues, but I am sure the eldest ones can have their resentments too and I thought it was well brought out at the end.
Chuck has been so good I don't want him to die but it wouldn't surprise me if they have something lined up for the end of the season to set up the road to Saul in the second. I have been pretty much wrong all the way so far, but I would guess that, now Jimmy has cut him loose and he has to fend for himself, he tries to go out and run an errand for himself and gets hit by a car or something like that. Something that will change Jimmy for the worse come season 2. I wonder if we'll find out what Kim was offered to get Jimmy to agree?