Hi Red, I hope your able to feel better soon.
I've been going through a lot of surgeries myself, not quite as difficult as what your dealing with, though.
I have been hospitalized quite often. Sometimes for nearly 3 weeks at a time and my birds have never forgotten me. They even start screaming their heads off when I'm arriving home in the car with my folks.. I don't know how they know. (My mom does tell them before they leave to get me from the hospital.. I guess they understand)
I usually get punished for a little while when I first get home, (a few days) unless I'm in a lot of pain. They seem to sense that and take it easy on me.
I just try and talk to them and tell them what happened. If I have 'boo-boo's' as they call it, I show the birds and I think that helps them to understand why I wasn't here.
When I had my umbrella cockatoo, Boca, she was always the first to forgive me. She would yell BAD GIRL and then launch herself at me for hugs and kisses.
Good luck, hope everything goes well.
Sarah