A personal opinion here, but I don't think the hardware will really be the problem. Many long-time Windows users have various levels of difficulty transitioning to the Mac. It could well be that the longer they've used Windows, the harder it is. User experience levels are also a big factor, I suspect.
A 'geek' can probably switch with hardly any problems, they usually understand the mechanisms inherent in any computer. They understand that the GUI is just a way of communicating between humans and silicon. They can usually adapt to different methods easily. Swap "control" for "command" usually does most of the work with keyboard shortcuts. It may take a while to realize there is only one menu bar instead of one for every window. etcetera...
Casual users may be much more intimidated by these simple changes. And it may be impossible to ever learn that closing an apps windows does
not Quit the program on a Mac!
Most programs that are duplicated on each platform have minor and sometimes major differences. Not only in appearance but in capabilities. Controls are often in different places, methods of doing the same thing are often quite different (usually easier on the Mac, but that is still a change that must be
un-learned and
re-learned.
While Mac users are confident that 'our' way is better/easier, we must remember that most of us have been doing this for a good deal of time. What is second nature to us can become extremely frustrating for a new comer. I suspect hat most of us would find it difficult, for varying amounts of time, to completely switch to Windows, even in Windows 7.
Finally, I think you should expect a possibly long-term period of 'support.' Long distance telephonic 'hand-holding is seldom enjoyable and can become extremely difficult when new words for similar actions are involved. And then there are completely new words for completely new actions!
"What is all this stuff with a little "i" in their name?" "Where is the File Explorer?" "Where is the Start button?" "Why are all those little picture things on the wrong side of the window?" "What do you mean by 'monitor,' why should I have to monitor anything?" "Why do I need an adaptor just to use my TV thingy?"
Perhaps I'm starting to exaggerate, but you probably get the picture. Perhaps Ed is very computer literate. I already know you are more patient than I am, of course, around 95% of the world fits [b[]that[/b] category!
I am suggesting that it is sometimes better for a person to keep using a familiar system than to be offered a 'better' system that may bring many frustrations for possibly a long time. While you may be able to grasp new ideas and methods in the computing environment, most people simply want to do simple things in a way they have already learned. They may have no interest in even knowing that there may be easier ways of doing the same thing or even doing new things. But only you know the details in this matter and you will have to live with the consequences! Not only in direct support but in the sometimes very difficult 'family' interaction! I know that your brother-in-law has a fantastic home and acreage to visit, I certainly wouldn't want you to find those visits become less enjoyable!
"Good luck, young Will!"
Be sure to let us know if there is anything we can do to safely help, family counseling excepted, of course!