It seems like a lot of fuss (and expense) to avoid the inevitable. If record keeping has any value (and it should!) then it is worth keeping your system updated. Otherwise, you end up in your friend's situation -- stuck with software that only runs on an obsolete, unsupported OS that's approaching twenty years old. A major part of running a business is staying current. If he isn't "open" to that idea, he should have someone else keep his books.

For a few hundred bucks, he can have a new computer and download GnuCash, an open source accounting program, free of charge. It is simple to use and runs on multiple platforms. If cost is such an issue, he can convert his old XP machine to Linux and won't even have to pay for an OS.