DEAR ABBY: I’m unsure about how to proceed with my niece. She is struggling with child-rearing and debt. Twenty-five years ago, when she was 16, my sister “Nan” and her husband threw her out on the street. I took her in for two years. Until she graduated from high school, she lived with me and my two daughters. She reconciled with my sister at the time of her graduation. After that I backed off, trying to let Nan perform her role as mom. I have had a bumpy road with my sister since then, but until a year ago, we ...