It doesn't matter how someone looks from the outside. People can put on a mask, and yet still feel all alone when they have no one around them.
I mean the best advice is to see a doctor so she can talk about it. And mostly don't force her to talk these things need to come from the person who feels this way.

They have to embrace what is bothering them, and that's the only way they can get out of it. They have to give everything a place in their mind.