Yuck. I can't bring myself to look at that video.
All I have to say folks is this-- Hire an engineer to inspect your home. Have roofers come out and inspect if the engineer can't get up there. Pull off siding and check flashing on decks and around windows. Take the AC handler apart and look for mold. Look for any water point of entry. Do a mold test if wary. If an owner won't comply in a sale, run don't walk.
I'm dealing with mold issues all because of improper flashing. It's costing me tens of thousands of dollars, not to mention mentally and physically draining. The owner/developer who had the house for years perjured himself on disclosures. I did have inspections, but did not do the above. A home inspector can only point out possible deficiencies but does not go to the extent an engineer would.