DEAR ABBY: My mom is in a home for dementia patients, and Dad was living in their big house by himself. He couldn't sell it until everything was settled with my mom. Because he was very lonely, I decided to let him move in with me. We agreed he would pay $320 a month. I needed the money and thought it was fair. My roommate pays $400 a month, but I was OK with Dad paying less.

When my sister found out, she was very upset that I was charging Dad. She had him move out that day, so now he sleeps at my brother's and spends most of the day at his house.

When I turned 18 and lived at home I paid rent, so I saw nothing wrong with it. Now I am an outcast. No one talks to me except my dad, by phone. I am very depressed about this and feel suicidal. I suffer from anxiety and depression, see a therapist and have been on meds for years. Am I wrong, and how do I fix this?

— GOOD SON IN PENNSYLVANIA

DEAR GOOD SON: If you haven't done so already, talk about this with your therapist. It is very important that he or she knows you are having suicidal thoughts and that they persist. You did NOTHING "wrong." Your father agreed to the arrangement, and he should have made that clear to your sister. She was wrong to interfere, and she seems to wield a disproportionate amount of power in your family. I can't fix that and neither can you, so you will have to find ways of coping not only with your depression but also with her. You have my sympathy.

Contact Dear Abby at DearAbby.com or P.O. Box 69440, Los Angeles, CA 90069.