The atmosphere, music, nostalgia and other things makes it the most enjoyable movie that I know. It's more of a personal connection that really an objective "this is the best movie ever made".
As for the point being, the movie is from 1982 and was on about a battle between sysadmin/ML/AI and users, its also a homage to a community which did not exist back then in the same effect it does now (the FOSS community).
He'd probably cope with recent Dune, which I thought was very polished. We should watch The Martian, as he read Project Hail Mary and liked it. From memory, Arrival would be good assuming some of the undertones went over his head. Contact is another good one in a similar vein (common element with Project Hail Mary and Arrival of decoding messages).
Although the events at the beginning and end of the film require massive suspension of disbelief I rate The Martian as one of my favourite films for presenting an optimistic view of science and engineering, massively realistic by Hollywood standards. I'd definitely suggest watching it.
They only tell you 15 years later that you scared the shit out of them.