have a read of
this article. File recovery can often result in losing filenames and their extensions (as the process involves raw reading of the 1s and 0s on a hard drive directly, which is seperate from an operation through the operating system so the process creates a new binary file but to the end user they don't know what the file actually is. The process of
filetype identification is up to the client to sort out. Its a massively time consuming process. This is where your friend is at now. Its part of the reason I no longer offer my services to people except in rare cases any more. Data recover can not be estimated how long it'll take or how successful it'll be and a drive full of hex numbered binary files and no directory structures means the client becomes a pest more often than not and its not worth the money or stress.
Data recovery services do NOT give you back a hard drive with everything looking to you like it did before the drive died (generally I can quickly tell the user caused the damage regardless what they claim).