Interesting. Around that time I was working at a place that was contracted to build and host binaries for zSeries/pSeries in support of IBM's Linux on the mainframe effort. We didn't actually use any of it. I think we were just there to make it look like there was 3rd party support, even though it was all funded by IBM.
1) Keep moving. Exercise and stretch. Even if it takes half an hour to get going, don't just sit in a chair all day or soon you won't be able to do anything but sit in a chair.
2) Go to the doctor regularly. Listen to them.
3) Encourage them to downsize their home and move into something wheelchair accessible or even assisted living before it becomes medically necessary. This can be really hard for some people to admit that it needs to happen, but it's A LOT harder for everyone when it's forced.