Why a relative replaced some perfectly good Michelin Tires?

Probably already been said , learn to plug a tire. You can do it with the tire on the car even in most cases in under 2 min.
Keep a kit in your glove box, every parts store has a cheap o section of roadside bits and tools...you'll find one there.

Other thing about old tires, mainly used tires that look glossy n new. You never know which direction the tire originally road all it's previous milege , neither does the tire jockey ..so the tire goes on, wrong direction and shortly down the road it bubbles and or tread separates and you get a vibration, perhaps in the steering wheel and wonder "hey I just got a tire that looked bitchin with fresh balance, wth ?!"

Never spend more than 40 bucks on a used tire unless you really know who owned them and how they came. New tires can be real cheap, too cheap to buy 50 dollar used.