Please, lets be very careful here. The description of a volatile, controlling, isolated relationship is not a healthy one. At the very least that would seem to suggest an emotionally abusive relationship. And often, where there is smoke, there is fire.
It's really, really common for abusers to claim that their victims are depressed, crazy, etc. Abusers are skilled manipulators and smooth liars with years of practice. They may come across as confident, secure, and sincere to court officials. They may even relish court proceedings as a way to continue to degrade and harass their victims legally. Battered moms on the other hand have suffered real, ongoing trauma. They may appear nervous, depressed, emotional, angry, etc. not as the result of any mental deficit or personality disorder, but as a direct outcome of the abuse. Abusers are only too happy to help paint the picture of a crazy or unstable victim - they seek to degrade her further and also to cast doubt on allegations she may make.
Judges go to law school, where they learn to frame arguments, cite case law, research precedent, etc. Little, if any, of their training is devoted to family dynamics, especially where control/abuse and family violence are involved. This is why 70% of abusers are successful in gaining sole or joint custody of their children. It's a scary thought and a HUGE obstacle that family violence advocates work to overcome.
So given her friend's statements about the relationship it would be wise to take any comments from the court proceedings about her mental state with a grain of salt.
Here is a brief, non-legalese article that talks a little bit about the problem:
http://www.deseretnews.com/article/660204579/Batterers-often-get-custody-of-children.html
Excellent research can be found by reading anything written by Lundy Bancroft, or checking out the websites of great organizations like DV Leap and the Leadership Council.
