ipad mini 3 16 gb

I sold my iPad Mini 3rd generation 16gb. The fellow that purchased it says it is slow and the games his son plays on it will crash. I asked him to run speedtest.net to check his internet speed but all he said was it was good. I used it on Spectrum internet for emails, streaming Netflix and news. It worked beautifully.

He reached out to me three weeks after the purchase to say that the unit is defective. I feel bad for him and suggested he sell it on FB Marketplace or Craigslist as he had just purchased but seemed offended because I would not take it back. He never said anything about how it was to be used.

Could it be that he is trying to run todays gaming apps on a slower processor with only 16 gb memory and that is the problem?