How much tax do you need to pay in this example?

Let’s say your dad wants to learn about crypto, he invests 10k of fiat send it to an exchange and invests all of it into Bitcoin. He doesn’t have a wallet or know how to open one or care to so he send it to your wallet.

He immediately thinks this is dumb as he says it’s a digital currency that has no value; he then immediately tells you to sell all the Bitcoin for 10k of fiat again and says ‘here son, do you want you want with the money now; just don’t invest it in crypto’

My question is, is this considered to be a taxable event?

If so, for whom?

And how much do we owe?

Thanks in advance.