Do not try to explain this to him. This person considers the Ponzi scheme all that has caused him a loss. The bubble and the pyramid are different things.
Don't try to explain him ponzi, but try to explain airdrop, which was pure scam. "We will give them airdrop, they will buy BTX and we will dump our coins on them". It is so obvious from this perspective. And then, BTX team talked about some reasons for airdrop and how "big marketing and developing is coming after airdrop ends".
In real world, someone would go to jail for a long period!