BR, that only works if you have the valid key to unencrypt the file. To successfully recover an EFS file you need to have the original private key, a recovery agent that is still valid meaning either a domain admin account from the domain that you were a member of when the file was encrypted(and still a member of that domain) or the local administrator account if it was part of a workgroup.

In this case as their is no recovery information, and all they have is the file, there is no way to recover the data in the file other than a brute force attack.

As a best practice if you are using EFS you should create a backup of your private key and store that in a safe location. Or in corporate world, make sure that you have created a process by which your users can request a recovery agent to unencrypt their files.

Bruteforcing AES encryption is going to be pretty much impossible for someone that doesn't even know where to begin.