I don’t know. But I suspect they bought some established websites via a marketplace like flippa, that had established earnings (traffic, ad revenue). They then swapped the Adsense account to their own, and discovered that the ad clicks were fraud / bots, which resulted in their entire Adsense account being banned.
Ah, that sounds plausible. I read "website purchases" as "online purchases"; it didn't occur to me they might be talking about buying actual websites.
Trying to figure this out, as well. Makes it sound like he bought some service that would optimize ads or increase ad CTR?