To pay in real money, he would have had to sell his fraction of BTC at the price at that moment. The reason for his regret is absurd.

I had 0,368btc . Bought it when price was around 19k$BTC . Had a debt 10k$ so decided to sell my bitcoin when price was around 46k$ to pay a debt with it . I had other options how to manage debt but my choice was to give virtual money instead of real . So now have biggest regret and fomo in my life (((

P.s never sell your $BTC