Being isolated without friends or a support network is a huge red flag for someone suffering from controlling behavior. It's what the WTS does to people, but way worse because it's total and complete and on an individual level. Even as a JW you'd at least have some friendly folk you could talk to in the local congregation. Without that you have nothing.
You don't have to be a super-outgoing party person but everyone should have at least one very good friend that they can confide in, discuss things with, get a 3rd party viewpoint from and rely on for emergency support if needed.
"I had a friend once but he didn't like her" is such a sad indictment of a relationship. I hope she starts to spread her wings and learns to expand her own social network so he isn't in such complete control of her life. It's not like she is the one in a foreign country so she has that advantage after all.