The bank is asking for a transaction history, but she does not have one because it was a donation.
What happens then?
In the future, I think it's gonna get much more difficult for banks to trace where exactly the BTC came from.
For most people it just sat there in a hardware wallet and the link to the original purchase is not hard to demonstrate.
But that will change over time, especially when BTC is regularly exchanged between people in different jurisdictions.
Bitcoin transactions are transparent. Let the banks first enable a system where it will be possible to check all previous hops that fiat money had, and then maybe they can demand the same from crypto holders.
For me, it is unacceptable that if I sent someone money, they come and ask for information about where the money came from.
So, just bypass such a bank and find an alternative option for converting crypto to fiat if you need it.