Where did he get the books? When I was a kid, the DOS interrupt bible was something I turned into a dog-eared nightmare. I wonder if he had access to technical books through his school maybe?
The books I had loaned out however were dated 1977 - 1978 according to a recent google search. Very obsolete for the time. I'm tempted to call the high school library and see if I can buy them, since they'd be even more so useless for any student who wants to get into programming now.
Better yet, it's just given me an idea, if they still haven't updated their books on programming, I might even see if I can buy a few good modern books on C / Python etc and donate them to the library, along with software. Who knows, it might stop someone else from ending up the same way I did.