Looking for a way to block someone from accessing a facebook account!

Hello,
I have a friend who's relationship broke down a while ago but the woman is now stalking him through his facebook which she is entering either from her Ipad, or through Itunes.. He is stressed about it, because she is sending messages to people pretending to be him, AND breaking down other relationships he has tried to pursue.. I have looked through privacy settings for him, but there doesn't seem to be anything that stood out for me that could really help him.. I was wondering if anyone else had an idea of what could be done? Is there a way to block the devices she is using to get into his account? He has also made new accounts, but she can get into his phone via the Ipad so nothing works.. He would change his number but he has a business and would have to re-do business cards, pamphlets, etc. Any opinions would be fantastic!