life really is nothing more then agravation most of the time isnt it?

Robert( my husband) and i have been living with my sister for something close like 8 months, and everyday it is another form of drama. she has 3 kids 15, 14 and 11, and each of them have more issues then she is willing to deal with. she jumps from guy to guy looking for anyone that would be willing to keep her from being alone, and in the meantime her children suffer. her eldest, is so screwed up in the head, and is in such a need for any form of attention from anyone, she has taken to making up separate personalities. i caught her looking up the symptoms of PT SD and multiple personality disorder online. her mother took her to the shrink, and low and behold she is now documented as having 5 different personalities including a British woman named Elizabeth, who doesn't even know how to speak in a British accent,. although the fake one she uses comes close. it ridiculous. her middle son, has a temper on him that is so out of control she finally took him to a psych hospital and had him committed. but she still doesn't realize her kids have issues....i try and support her every decision, but it is just getting too much now, and my marriage and my relationship with my own daughter is starting to suffer....i have no idea how to get out of this situation, with out causing harm to a friendship that has lasted pretty much my entire lifetime....................