Please please please I need help i think my brother has become a victim of crypto fraud

My brother has invested some money in some Bitcoin thing, I don't know how authentic it was. Previously he was able to get the small amounts back so he thought that it was authentic. Like an idiot, he invested 100k and profited it to 200k, while withdrawing, they said some error happened and his account got frozen. So they said, transfer the equal amount to unfreeze the account. He transferred and then they unfroze the account but said if you want to withdraw all the money, you have to increase your balance till 1mil before withdrawing.

Now we don't have that sort of money. What should we do? I don't need the the profits. Just the money that we had sent.

Any help would be appreciated. Please anyone. Help us out