I still don’t get the correlation between chatting on Facebook and someone loosing offline wallet, the only way it would even have been possible is on online wallet, except maybe during the cause of the chat, he must have been carried away with the woman he was chatting with lol, and then exposed his password and his private keys to the person which should have been kept as secret, or could it be that he visited a site that had malware and them got installed on the computer which was able to give them access to the offline wallet.

The best way he can protect his offline wallet is to have it in a gadget he will not be using to visit all these websites, or just make use of hardware wallet like NANO because those are still the ones that can actually give him the safety that he needs and even at that, he needs to be careful of the information that he gives out when having chat with someone irrespective of how close the person is.