I think that we can't shield our children. We can be reasonable in our expectations, and we certainly don't want to overwhelm them. But hiding things from them... they know. When things were getting bad with my husband, I was worried about the kids, and I bought a few books about what to do when a parent is chronically ill. One thing that came up over and over was that the kids always knew something was up, and not knowing WHAT that thing was, was worse than getting an age appropriate explanation.
Of course our children do need our time and attention, and it is important for each of us to find our own ways to do that w/in our own pain and physical limitations. But if you brainstorm and think of things you CAN do instead of focusing on the can't, you will find that there are always options (lessons from my functional restoration program!)
With their dad being now completely a quad and me being somewhat disabled too, my kids have to adapt. But living this way makes them more aware of disability and therefor far less likely to treat people with disabilities as people who are "less than" or looking through them, etc. They have more compassion and sensitivity than other kids their age. While they are pain in the butt kids, when I need help, or their dad needs help, they are always willing to do what is needed without complaining.
And yes, they have chores, partially because I can't do those things. But honestly they would have had those chores anyway at some point, because that is what I believe in.