His betrayal had a purpose, that Castiel had already come to terms with. Balthazar had every reason to warn Dean and Sam and to stage a coup and had he actually been willing to listen it would have saved them all some bloodshed.

"No. Well, yes, but also no." He had been dying and he's not fully functional to begin with but better than he was. The yellow tinge to his skin and the slightly less shaven face punctuates that without him having to. "It's been years."