Thank you for your response. My issue here is that my father would be purchasing the cryptocurrency from other individuals (mostly family friends or other family members) and not an official exchange and so It's difficult to have a transaction track record. Perhaps an unofficial letter/agreement can be produced.
What I find strange is why I would be responsible for unrealized capital gains of a non-US citizen. For example, if my father who isn't a US citizen or resident is gifted a crypto currency at a cost basis of $0 and then gifts it to me and the FMV is $1000 at the time of the gift. The capital gains tax I would be paying is due to a capital gain not incurred by a US citizen or in the US.
