You say he's thinking CompSci. A few closely related paths could be Computer Engineering or Electrical/Electronics Engineering depending on his interests. He's still young so he has lots of time to explore and figure out which path is the best fit for his interests and/or desired career options.
The Stanford courses, to me, are more the Engineering side of things. The list is pretty much the list of math courses/topics I covered many moons ago taking Electrical/Computer Engineering. Possible careers - software/firmware/hardware design/verification. All of that calculus and differential equations is required to get into the hardware/analog side of things which IME is not really done in the CompSci path. He could still end up programming if that is what he's interested in.
More on the CompSci side of things are the ones listed under Coursera Introduction to Discrete... I'm tempted to have to look at the Cryptography course myself - thanks
I work with it all of the time so I've picked up a few things but I'm curious to know what gaps I have.
Many companies aren't picky about CompSci vs Engineering and over the years I've even worked with a few Physics and Math majors as well. There are some careers/companies/roles that are more specific though so it would be good to explore options to see what he thinks will be a better fit for him. As one example I don't think I've come across any CompSci working in chip design (even though there are roles where most of it is pretty much programming). On the flip side, I'm guessing there are niches/companies where CompSci is more prevalent but that I never see because of my degree/role.