It doesn't sound like he was selling bitcoins but rather running an "investment service"
I remember he had no problem to return the money with a small percentage.
Likely when bitcoin when south (talks about starting when BTC was $18 USD) he began operating as a ponzi scheme offering guaranteed returns to pay investors who had already lost.
Just speculation and google translate is horrible but it doesn't sound like it was just a straight exchange of fiat -> BTC.