100% in a month is possible, but only by taking extreme risks. I see on the site that he only wants your account number and password. That means no
LPOA and no contract. If he crashes your account, you are out of luck. If he makes money for you, your broker may have the legal right to cancel the trades.
Someone like this could easily trade two accounts in opposite directions with extreme risk. One client makes a lot of money and pays high performance fees (before a possible cancellation of trades by the broker). The other gets a margin call.
Never use any account manager without an LPOA in place and a contract specifying risk levels.