You could try a companion to cut down on his need for your attention (assuming it works out and kitty doesn't go into a jealous rage), but...I hate to say it, talkers tend to talk. There isn't much to be done for it (that won't drive you both crazy. :) )
...perhaps he just has a lot to say? After all, with the state in the world...maybe he has the answer and is frustrated no one is listening. :)
I am seriously considering getting him a companion, as he must be near me at all times. I really enjoy his company but when I am trying to cook, I am tripping over him all the time. He is the nicest cat I have ever had though!
Is it possible to get him a companion. Not necessarily a kitten but maybe a cat around his age? It would give him someone to play with or bathe or just be around other than just you. He could just be lonely.
It sounds like your cat has anxiety,,too. I am sure that a lot of it is from the loss of his brother just before christmas. It seems that the two of you could really help and support each other...he needs a lot of brushing, petting, attention, and I think that in return, you would also benefit as it is quite proven that the interaction between pets and people lessens anxiety. Yes, now he thinks that the crying will lead to a treat, as you have basically been rewarding his crying behavior. It may be very difficult to break that habit if you are going to try to do that!