I was out exploring one of those crannies you can find in a city and ran into a cell phone antenna kinda nailed to a water tower. It was sitting there with its butt hanging out, gated on one side and totally open to about a half a million people on the other. (If they were willing to bushwhack a half a mile) It had an expensive looking mini container looking thing under it. Not even one no trespassing sign. Sort of random don't ya think?
You can tell your brother they don't work after a hurricane takes out power. No cell phone works and people don't understand why my house phone still works - it's because that one plugs directly into the wall. My son called me from England after Ike came through and my house phone plugged into the wall worked. No cell phone worked.
I don't plug in the charger to the solar panel unless I'm recharging batteries so the greater part of the time the solar panel has nothing attached to it, no reason to have the charger plugged in. An EMP from a nuclear blast “might” damage it if the charger was attached and batteries in the charger, but an EMP from the sun would not harm it as the charge goes directly into the grid and not into anything outside the grid.
You believe whatever you want and I'll believe the scientists who did the tests and have the knowledge to differentiate between the types of incoming EMPs.