i'd stop and ask what was wrong. i'd do it for anyone.
i was at the airport one time and this girl was sitting at a bench right after security check and she was crying. no one stopped to console her or anything, so i walked up and sat down next to her and asked if she was ok. she said "yeah" and i said "well, obviously not... you're crying. can you tell me what's wrong?" and she told me about how her flight got canceled to cleveland or something and she really needed to get on that flight to see her dying uncle. he was saying his goodbyes and she needed to be there. she had to wait a couple hours for the next flight out. i consoled her and told her that it'd be ok and hopefully her uncle had enough strength to hold on until she got there later that afternoon. after i said that, she got a phone call... her uncle had just passed away.
i asked her if she believed in God or heaven and she said yes, so i told her that if she does, she should know that her uncle is probably looking down on her right now and knows how sorry you are for not being able to make the flight to say goodbye in person. i also told her that it might be a good thing that her last memories of her uncle were of him looking healthy rather than in a hospital bed, emaciated and weak with cancer.
she ended up calming down after she realized i was right and thanked me. she said she'd been sitting in that bench for over and hour crying and no one cared enough to talk to her.