Overheard on a bus

Now, this is a question of bus etiquette. A few days ago, I was on a bus, and a couple of teenage girls got on, about 14 or 15, and sat in the seats behind me. For your information, they were rather pretty.

One of them received a call on her mobile. She quickly became emotional, and it became clear thst her boyfriend was ditching her. Not in person, you understand. He got his brother to do it. Yes, you heard right. His brother. Saddo. Now, the brothers were in the same room; it was clear from the conversation, that the brother who was doing the ditching was shouting instructions to his sibling, who refused to come to the phone.

After an emotional exchange with this hapless sibling, the girl dissolved into tears.

My question is...

Should I have done what I was very tempted to do, which was swivel round, tell her that she was a very attractive girl, and that a chap who would break up with somebody by getting his brother to do it, was an utter and complete saddo...?

Or should I just have done nothing but listen for my own entertainment?