A lei of aloha and prayers to you with the hope of a full recovery!
I agree that you and your family will love Universal. It is new and exciting and very compelling. It will keep your mind fully occupied - IOA is a total experience. Each area is themed in both sounds and sights. It is like those Waldo books, everywhere you look you see something new and exciting. I think it is edgier than Disney, at least it isn't as "sweet".
I think you will be able to ride most of the rides except for Back to the Future and maybe the coasters (although I saw a children's special this past week end that said coasters are less likely to cause motion sickness - I intend to test this when I go next month! LOL) Last time we went, we took our grandsons and one gets motion sickness very easily (even once when I swung him too long on a swing!). He did not feel sick on HannaBarbera, Cat in the Hat, Spiderman, or any of the rides in Universal. He didn't go on MIB (it wasn't opened) or Back to the Future (I had heard it was rough). So I would think there could be alot you could do in the parks.
We spent 3 days there last visit and we did not get to see or try everything. So next month we are going for five days. So obviously, I do think you can make a very enjoyable vacation out of it.
I plan to take my time and really enjoy the parks next time. I guess if you are into commando style touring you could do it all in 2 days...but I would suspect your kids will want to try things again and again and like I said there is so much detail, once through a ride is really not enough.
Universal has a vacation video that would give you an overview of the parks. You can order it on their website. There is a toll free number, but I cannot find it...sorry. Maybe someone else will read this and post it for you. (Please)
Again, I wish you good health.