Financial Proof for Derivatives Trading


I have a question, i used to trade in the stock markets from a account in my name and my portfolio size was in the 7 digits. The company i work for changed it’s policy from April 1, 2020 because of which i can no longer trade in my name. So, i cashed out and gave the entire 7 digit portofolio to one of my relatives and lets just say my relative started trading in derivatives market from their account with that money. But now my relatives broker is asking for financial proof for the huge cash pay in. My relative was paying taxes every year but not to the tune of the pay in.
So, my question is how can it be proved that the money is from a legit source?

They are asking for the proof according to the AML policies. You can ask the broker what exact proof they want. Mostly a written confirmation along with a bank statement showing the transaction detail will suffice the requirement.