One of the quickest ways to destroy a relationship is by fighting over money. And the battles can get particularly ugly and hurtful when they are among family members.As part of a new feature, I’m inviting you to send me your stories about a monetary dilemma in your family. Who do you think is right in your family’s financial fight? Let me help you figure it out.To that end, here’s a predicament one reader wanted me to help her with.The family background: She’s one of three daughters of divorced parents.Two sisters are married and employed but don’t have children. A third sister, who works part time, is divorced with a teenage son.The financial background: As it stands now, their 82-year-old mother’s assets will be divided equally among the three daughters.Since the one sister’s divorce, she has been living at her mother’s condo without significantly contributing financially to the household.For a time, the sister’s teenage son also lived there. Neither parent of the teenager has saved for the young man’s college expenses. “Basically, both are banking on my parents to pay for their son’s education,” the reader wrote.The conflict: Recently, the mother moved to an assisted-living facility. “Meanwhile, my sister continues to live in my mother’s condo. She has begun, for the first time in nine years, to pay the utilities and other bills. Otherwise, she and my nephew lived there for all those years with my mother paying for everything.”Perhaps the sister isn’t factoring in the care her sibling gave to their mother in exchange for living there.The sister who corresponded with me is upset that her sibling is pressing their mother, who has cancer, to put something in her will to pay for her grandson’s college education.“My nephew is a nice kid, but he is not much of a student and I have doubts he’d make it through a four-year college. My mother’s assets are fine, and she can afford to give him money for college. But I personally feel it would be a waste of time and that he might want to try working a bit and do a little maturing.”The dilemma: The correspondent sister wants to know if she’s wrong to feel that it is the parents’ responsibility to pay for their son’s schooling.Shouldn’t her sister use her own inheritance instead of seeking a separate award for the son, she asked.The grandmother wants to do something for her grandson and has talked about establishing a trust for him.“She doesn’t understand that someone other than my sister needs to be the trustee in charge of the funds. My mother is one who always helps the underdog, and in this situation I feel like she is rewarding my sister for being needy and irresponsible.”The bottom line: This is a common problem in many families.Ageing parents are taking care of one or more of their not-so-responsible grown children. One or more family members are concerned that the parent or parents are being bamboozled.In this case, I would assist the ailing mother in finding a good estate attorney. The attorney can help her determine the best way to will her money, including leaving some in a trust to her only grandchild to go to college.That’s a kind thing for her to do.If there is a concern that either he or his mother will waste the money, the grandmother can set up the trust and designate a responsible person — perhaps someone not in the family — to oversee the distribution of money from her estate to the young man.Before seeing the attorney, do some research on the difference between a trust and a will. Nolo.com has a good article explaining the pros and cons of each. Search for “living trust v. will.”Who is right in this type of financial fight?I believe parents should, as best they can afford, pay for their child’s college education. Indeed, the sister could do it with her share of the mother’s estate. So yes, it’s quite audacious for the sister to push her ailing mother to pay.It’s reasonable to be concerned that an irresponsible adult child is taking advantage of the generosity of an ageing parent.And yes, it’s fair to voice your concerns and even take steps to protect her assets so she won’t go broke. But in the end, it’s the mother’s money to do with what she wants.If you’re mired in a money dispute with family members, send your story to colorofmoney@washpost.com. In the subject line, put “Who is right in my family financial fight?” You can remain anonymous, so you won’t have to fight about putting your business in the street.Readers can write to Michelle Singletary at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071, or singletarym@washpost.com. Personal responses may not be possible, and comments or questions may be used in a future column, with the writer’s name, unless otherwise requested. To read previous Color of Money columns, go to postbusiness.com.