I like this thread. This is the kind of stuff we need to talk about.
I didn't see "Comms" on that list -- or anything electronic. In fact, he specifically said "Mechanical engineer" as if electrical, electronic, or software engineers will be useless.
Don't kid yourself -- all computers and software aren't going to go "poof". The entire national electric grid (from sea to shining sea) could go poof -- and yet being able to wield electronics and/or software would give your group an advantage.
"HOW!?!?!?!?!?!", you might say. "The power is out everywhere. AUUUUGGGGHHHH!"
Um...ever heard of batteries? Solar panels? Wind power? Water power?
And this isn't 100 years after a collapse, when everything has turned to dust. There will be salvage opportunities for YEARS for everything from batteries, solar panels, computers, wires, cables, electronic components (resistors, capacitors, inductors, transistors, crystals) -- virtually ALL of these things you find will be in "great" condition, because the collapse happened only hours, days, or weeks ago.
Now 50 years after the collapse, unless everything ramps back up to our current level of technology, all cell phones, tablets, computers that were built will start to decay and will become more and more rare. Supplies of all sorts of repair parts will become rare to the point of non-existent.
P.S. When I say software engineers won't be useless, I'm not including "web designers" or even "web developers". The Internet, would indeed be gone-ski. DevOps, deployment, cloud technology -- many of those things would be more useless than a blacksmith is today. Someone who can easily integrate a new API or library into a website, make changes to the layout of a website, and even full stack developers will be pretty useless. But REAL programming -- being able to write code even at a low-level -- Arduino or PIC for example -- would be quite useful. You'd have to be a 70's or 80's style programmer, in other words. You won't be writing large, bloated apps for Apple, Windows, or even Android/iOS. And you won't be making websites.