Oh my goodness
. He literally has made a very costly mistake. I too have come across some recovery technicians however all were online and therefore just like you mentioned I really can't recommend them since they don't guarantee safety of his data. I am not an expert anyways I think technicians have some way they can recover data from a formatted hard drive that is if the specific hard drive meets some certain conditions. I believe we have some nice tech guys on this forum who hopefully would be able to render some help.
I think most hard drive recoveries have to be done physically by the technician. Probably if it turns out so a technician here could guide him through a possible option for the restore process. +1 for you op for trying to assist him. I hope he is able to recover the data he lost.
Data lose or lost data occurs either intentionally or unintentional. To prevent it from happening, I think the following ways can help if been adopted. which are;
1.Update your files.
2.Protect your hardware.
3.Make sure your employees have knowledge about data leakage.
4.Make your computer clean always.
5.Application of antivirus and anti-malware software.
6.Develop robust security policies for devices and endpoints.
7.Ensure sensitive data is encrypted.
Keep software patches up-to-date.
OP, If your buddy chose the quick format path, odds are decent that most of the data might still be recoverable. But fetching those formatted bits is no sure bet and whether the recovery sticks depends on how thorough the formatting was and what got written over those sectors in the meantime.
Hard ware security is essential to prevent data lose. It should not be over looked.
While most data are now stored in the cloud, hardware devices are still necessary to access it. Those data, especially the critical ones that reside on them can be lost when damaged or compromised. Attentions need to be paid to them. the following precautions need to be taken to avoid such from happening;
1.Anti-theft equipment needs to be installed.
2.Also install circuit breakers.