I'll be hoping and praying with all my heart that he will be okay...

Aerobolt....I know exactly what your experiencing right now from my own experiences. My grandmother had a stroke and soon after broke her head open at a nursing home, and I had to be her caregiver for a year until she died right in front of me from heart failure and diabetes. I'm not going to lie to you because you deserve to know the truth: It will be more painful for you and for your loved ones than for your uncle... He is eventually going to accept his condition and while he declines detach himself from this world.
Death is a very unpredictable thing....though it greatly saddens me to learn your beloved uncle is dying, I'm glad that you were able to find that out instead of it just happening too suddenly.
Whatever you do, spend as much time with him as possible, tell him you love him, share memories with him, embrace him, and...once he's close to his end...tell him that it's okay...that you're there right beside him.
I'm crushed to know you're going through this, because I understand. I'm here for you Aerobolt so please, please talk to me when you need to, and especially when it's....time. I don't want you to be alone when that happens, all right? Me and Toudou are here for you.
Hang on, my friend. The coming days will be very tough, and the silence afterwards strange, but everything will take its course and, what matters most of all, your uncle won't be suffering from all of those horrible health problems any more. He'll be set free.
I'm sorry...*hugs tight* I will be praying though, for you and your family, I promise.