I'm so sorry for what your little guy is going through and hope you both find solutions for an eventual transition.
I did see a Caesar Milan episode with a blind yorkie (who was fairly young, not frail) who turned very insecure and would just stay in his crate and bark. I don't remember all of the specifics, but the general lesson was that the owner was cottling the dog too much (because she felt so bad for him), not being the pack leader or offering any discipline, which led the dog to his over the top insecurity. Caesar's advice was to treat the dog (and any dog with a handicap) like you always would and give them the leadership and attention they need to stay secure, while not giving up your alpha-dog role. They also sense your worry and fear, which feeds into theirs.
Of course all is easier said than done and I can't imagine going through it, but I just wanted to wish you well and give you a head's up to what I saw on the show.