He could make a lot of money selling to user groups for those older systems. I know there are local TI, Apple, Commodore, Atari, groups here that would love to get a supply of replacement parts for their systems.
The Museum sounds cool, I thought of doing that myself once but decided it would be better to have a Cybercafe instead with a showcase of older computer systems and parts.
He's near retirement age and (from what I can tell) is okay for money. Might as well have a hobby after retirement, I suppose. (He stops at almost every computer show or ham radio convention he passes, it seems; most of them, I've never heard of.)
"Beware of bugs in the above code; I have only proved it correct, not tried it." -- Donald Knuth