Cryptolocker: virus that steals data from the PC

A friend of mine's uncle fell into the trap and found his computer documents encrypted, very important documents. I don't know how it ended up. There are 3 versions of this virus. For the first two, there is a tool for decryption and virus removal; for the last one, there is nothing at the moment, also because it uses an RSA key with 256-bit encryption, making it practically unattackable. One must be careful not to catch it because, obviously, even after paying the amount, it's not guaranteed that the restoration tool will actually be delivered, and the amounts are exorbitant. 500 euros in bitcoin to be paid within a week, otherwise the cost of the tool doubles (1000 euros). One can partially resort to Shadow files, but they are not always present.

It happened to an acquaintance of my brother (to whom he himself had lent a laptop), but I don't know which version it is.

As you say, inaccessible data and probably unrecoverable.

It depends on the version of the virus... Up to version 2 there is a decrypter, from version 3 onwards there is nothing.

Maybe it's the 3, we have some programmer friends, people who anyway know how to use the pc in depth and no one has hypothesized a solution, maybe they were already aware of this virus.