You mean a guy who sells crap to preppers?

...Who has never published in a peer reviewed journal on EMI or anything relating, remotely, to grid infrastructure or power control, etc?

...Who has zero background in electrical grids? He worked on cables in spacecraft. That does not apply to national electrical grids. Do you ask your dentist for his opinions on brain surgery?

...Who is basing everything off the assumption that none of the last fifty to sixty years of improvements in grid control, monitoring, and protection don't exist?

Neither pulse does anything because modern electrical grids have tens of millions of arresting devices, extensive monitoring, and extensive self protection devices at nearly all levels? At least in no small part to be able to handle the millions of lightning strikes that hit grids?

Every substation you drive by has a controller that watches voltage, current, and frequency and nearly instantly disconnects the substation from the grid if parameters exceed safety margins.

A HEMP would cause widespread electrical outages. It would not fry everything.