Mom can't stay calm

Three year reader, first time poster.Our two year old isn't exactly the best sleeper. She typically sleeps about 7-9 hours a night, and if she naps, it's not usually for more than an hour. Daycare is different (two days a week): there she naps about 1.5-2 hours a day.We've taken her to several doctors. They all basically say: she looks happy and alert, I'm not concerned. Her mother gets frustrated by this, because she's read and been told that our daughter should be sleeping closer to 10-12 hours a night, and having a 1-2 hour nap.The really tough part is getting her to go down to bed at night. Mom has decided that she should be going to bed around 7:30, so that's when we try to get her down. Unless she's had a completely exhausting day, she usually doesn't get down before 9:30-10:30. Some nights, I (Dad) will put our daughter to bed. Other nights mom will. We both get frustrated, so there's usually a tag off in there. Some nights, mom just says "I've had it!", and leaves the room to go to bed. If it's a good night, I get our daughter down, and that's the end of it. Other nights, she'll start yelling instructions on what I should be doing from our bed room. Things like:Stop talkingTurn off the lightsPut her to bedSometimes, I can get my daughter to ignore it. Other times, she starts crying for mom so that she can get a hug from her. Sometimes this calms mom down.Tonight was the worst one so far. We're on vacation right now (aggravating factor), sharing a space with mom's mother (Grandma) & step-father (Grandpa). She walked out of our daughter's room, and started cursing: "I've f###ing had it with her! I'm f###ing done!"Grandma stepped in. I was incredibly frustrated, and confronted Mom about this, pointing out in my mad but quiet voice that this behavoir of yelling:doesn't help our daughter get to sleep, and probably makes it harderaggravates all the adultsis embarrassingShe responded (still yelling) by saying "I don't care, I'm mad". I totally messed up here, because I said "you're being a brat." It's the first time I've said that to her, and it was a dumb thing to say. I'm not sure it mattered, though. She just kept yelling about how I was abusing her and didn't care about her frustration. After about fifteen minutes of this, I realized attempting to reason with her was not working, so I left our room.She has been diagnosed with depression and anxiety, and I suspect she has PTSD. She's been offered meds by her post-natal psychiatrist, but refuses to take them, because they make her feel emotionally dead. I've asked her to try exercising (pilates, yoga, jujitsu, ultimate frisbee--with or without me). There's always a reason for her not to do it. "It's too far", "It's not easy with so many racists" (she's of east Asian descent), "I'm too tired/depressed". Similarly, she won't find a psychiatrist or therapist on her own, because she's only found one she likes, and that therapist moved away.I'm frustrated, angry, and disappointed. Our daughter has started yelling at both of us when she gets frustrated, and I suspect it stems from this. I'm on the verge of filing for separation, because I don't think I can make the situation better for Mom, and I think it could make the situation better for daughter, but that means I don't know what will happen when Mom has her. I still love her, but I'm realizing this is an abusive pattern, and I haven't found a way to stop this.Sorry, I know there's a lot to unpack there. I can see an argument for this going into /r/relationships, too. Thanks for reading and your responses.TL;DR: Mom quits when she gets frustrated, but yells from other room while I'm trying to get our daughter to sleep. via /r/Parenting http://ift.tt/2ssf7sY