Unfortunately, Bungie cant do anything to get your friend's character/gear back. It is their official policy to not recover lost/deleted items under any circumstances. Also, regardless of how trustworthy someone seems, no one should be giving out account login credentials. As such, you should have your friend immediately change their passwords on the ps account to prevent further damage. You friend wasn't hacked, as they gave their login information freely to the other person. While it does suck that the person did this to your friend, there is unfortunately nothing really that can be done.