It smells fishy, DON'T US! You have acquired that amount and you involve yourself in a crypto business and suddenly you didn't know how to cash out or to convert it to a real penny? Well, for the sake of humanity and goodwill, you need to backward, start it with number one, how you acquired that amount, then do it backward. For sure before you creating your first wallet you read a lot of articles and video on how you doing it right, I think no one here will ride you trick/
He said he found the wallet inside his brother's pc but what is only strange is he knows what those 12 words are called. He just said that it was a key, so indeed that this is fishy. I think I saw a similar trick like this before but I didn't search further if how it works but I think it works like this> once we entered those 12 seed phrases, our main wallets will then be infected by some kind of a malware which can then steal all of our cryptos.
Or maybe this can be the same on terk and metakings tokens, where you will be needing to pay some fees first in order for you to unlock the coin and after that, you can now trade it for other real cryptos.