It's just a PBN site. I'd de-activate the domain, delete or clientHOLD, for a simple reason: Don't underestimate pissed people, they can be like stalkers: They spend hours or even days of research to find your identity and ways to hurt your business, they hire lawyers for a lot of money, they report you to Google for spam, they use the Google DMCA form, they send e-mails to your registrar, your host, the merchants you advertise on your money site, every contact they can find. Not a joke, there are people making this their personal crusade and devote their life to it.
Btw, selling the domain back to him could get you in trouble for cybersquatting, even if the domain expired. A lawyer could easily turn this into a "bad faith" thing.
Sidenote: Legally, it's not just his logo, it's his content, too. You have no right to use it, just because the domain it was on expired. Copyright doesn't work this way.