The old car posted usually very cheap like 20% to 50% cheaper to market price

From the advert no mileage stated, sold out within minutes. Buyers couldn't even test drive

So any advice?

I've tried selling to him before he got famous (old S Class)

He asked the right questions regarding the suspension ,etc and made on the spot offer (on call) & wanted to view the car same immediately which was like at 1AM at that point. 
i've also talked to my mechanic about a W201 190E at his shop. Found out the owner got it from Akash, condition was surprisingly well & the guy spent additional like 5-8k to restore the car.

I believe he sells drivable cars, only need to do the typical wear & tear. IIRC there was also a W212 at my mechanic which needed 5k in suspension works done

Buying from him , nowdays is crazy.. you need to make a split second decision.. Last time when he was just selling on Old Merc Groups took him 1-5 days now only takes him 15-30minutes to sell, super happy for the guy though