DEAR ABBY: My 63-year-old mother has recently been diagnosed with stage-4 metastatic lung cancer. Even prior to her diagnosis she was a negative and depressed person. She has been a smoker, drinker and backseat driver for almost 50 years.

She has undergone intense radiation but is refusing to take her chemo pill. In her words, why should she prolong her life by another year, especially if it causes more side effects and won’t cure her? My twin and I are her only children. She has no significant life partner, and there are no grandkids.

While I have kept in steady contact and maintained relations with her even during all our bad times, my brother has taken an “out of sight, out of mind” attitude. We both live a two- or three-hour distance away from Mom. The problem now is, my brother wants her to persevere through all the doctors’ treatments, while I have accepted her decision to essentially let go. How can I help him come to terms with Mom’s decision, and do you recommend any resources? — SON/BROTHER IN CALIFORNIA

DEAR SON/BROTHER: I firmly believe in a person’s right to make their own decision when it comes to continuing or discontinuing treatment for a terminal illness. If your mother feels the chemotherapy has side effects that are too debilitating to tolerate, it should be her choice whether to discontinue them rather than the preference of your brother. If your mother prefers palliative or hospice care, she is entitled to have it, and she should discuss it with her doctor, who can see that she receives it.

Two excellent books will provide the information you are seeking, and more. Read them and share them with your brother. Both include the topic of physician-assisted aid in dying.

The first, titled “Finish Strong,” is written by Barbara Coombs Lee, the founder of Compassion and Choices, an organization to which I have been a longtime contributor. For free resources regarding your mom’s decision, visit www.compassionandchoices.org.

The second book, authored by Diane Rehm, who hosted “The Diane Rehm Show” on NPR from 1979 to 2016, is titled “When My Time Comes” and will be followed by a documentary to be aired in the spring of 2021 on PBS.

DEAR ABBY: I’ve been happily married for a few years. Prior to getting engaged, I had a close friend I had feelings for, but nothing ever came of it. We have remained close and see each other throughout the year at work conferences (he lives in a nearby town).

I have realized the feelings I have had for him over the years haven’t gone away. Should I tell him how I feel or forever keep my peace? — HISTORY REPEATING IN ALABAMA

DEAR HISTORY: History isn’t repeating itself. It’s the same old story playing in your head. Ask yourself what you have to gain by telling him you still have romantic feelings for him. If the answer is trouble in your happy marriage, then keep your trap shut.

— Dear Abby is written by Abigail Van Buren, also known as Jeanne Phillips, and was founded by her mother, Pauline Phillips. Contact Dear Abby at DearAbby.com or P.O. Box 69440, Los Angeles, CA 90069.