Q. My kid sister is 17. She has had a pretty normal, dysfunctional youth (parents divorced, changed schools, boyfriend drama) and is going through her “rebellious stage.’’

She opened up to me about doing a drug called Molly (MDMA) a few times.

Each time she told me that it was the last time she would take it.

I had experiences with the same drug when I was younger. I have seen friends use it habitually. Luckily, I was not one of them.

This summer, she decided to drop out of high school. My mom signed the papers, for reasons unbeknownst to me. I tried to talk to my sister, but she stormed out and blocked me in every way of electronically contacting her.

A week later, my older sister and her husband went to a concert with us. We ended up bumping into my little sister and realized she was on Molly. It scared me, but I just tried to stay by her and keep her safe. That night, on the way home, my older sister was so worried that she had a panic attack.

I told my older sister I felt the need to speak up. She said she would rather not tell our mom because she didn’t think my mom would stick to a punishment, and she wants our younger sister to trust us enough to talk to us about these things, but finally said, “I will back up whatever decision you make.’’

I reported this to our mother. Now, my little sister hates me. She won’t look at me. She will speak to my 3-year-old daughter, my husband, and my older sister, but not me. My older sister has not backed me.

What should I do? Sad

A. MDMA is a potentially very dangerous “party’’ drug.

Your sister is reacting to you in this way because she is 17. She is immature and is trying to punish you. Your older sister is employing a common tactic not to make waves in hopes that the teen keeps talking. But if the teen reports what she’s doing and nobody does anything, what’s the point?

Your mother seems to have given up on her. Don’t do the same. She doesn’t need to be punished as much as she needs help, some structure, and the realization that she matters in this world.

Tell her, “I’m not giving up on you.’’ Don’t take it personally when she won’t interact — she is listening. Offer to help her. Find a counselor for her to see and take her, then take her out for coffee afterward. Listen to her, without being judgmental or preachy. Help her to find a part-time job while she gets her GED. Continue to care and to believe in her. It’s OK if she hates you right now. Love her anyway.

Q. I have to add my point of view to all these questions concerning Facebook.

I simply fail to see the upside to using this social media platform. It does nothing but create problems for people! Facebook Free

A. I disagree. I’ve connected (or reconnected) with many family members and old friends on Facebook. I’ve also made many new friends on the platform.

Amy Dickinson can be reached at askamy@tribune.com.