Update:
In the past couple of weeks, there have some big changes for my uncle, and thankfully they've all been for the better. His heart rate has begun to return to normal, he doesn't appear to be experiencing the pain and discomfort in his side which seems to suggest the antibiotics have been working. They've removed the ventilator and he's awake and breathing on his own, although he is slightly out of it. A few times he would say things which made it clear he thought he was back in his wheelchair, and some of the things he says just don't make sense. It'll be a while before he's back to his normal state mentally. They say he isn't totally out of the woods yet, but he's much better off than he was weeks ago when doctors were basically giving him a death sentence.
Thanks again for all the thoughts and prayers, I have to believe they had an effect.