The problem with that line of thinking is that she also refuses to let Jace get the help he needs. She's frequently refused to take him to therapy, opting instead for a faith-based approach to his mental health. While she might have good intentions, she's going about things in a manner that severely cripples his ability to grow past the man-child he currently is. He's shown a strong desire to grow up and "learn civvie skills" in the last few streams, but living under gail's roof, that's frankly never going to happen.
I'm not sticking up for Gail. My sole point is we don't have all the facts about her. Most of what we suspect about her comes from Jace himself, and he's hardly reliable. He exaggerates to get attention. "Faith Healing" may, I repeat MAY, simply be Gail taking Jace to a counselor at her church, and many of them actually do have college degrees in psychology, such as with the Catholic church. I'm not saying definitively that this is the case, I'm simply throwing it out there as a possible scenario.
Let's not forget that she successfully raised Rob to be a well rounded adult from what we know of him, though he was adopted according to Jace so if she does have a schizoid disorder he wouldn't have the same problems that Gail and Jace have. But Rob is proof that she isn't a total failure as a parent. My sole point is that we shouldn't be going off half-cocked about Gail when the majority of what we think we know of her comes from unreliable and biased sources (Jace and the few appearances she's mad in his videos). That's all.