If you saw someone upset and didn't know who they are, would you ask them if they are okay? If yes, what is the first thing that will come to your mind before you talk to that person?
I would like to go and talk to the person and ask him to calm down. The first thing to come to my mind will be the reason for his/her crying. I will try to console him and talk him out from his depression, will try to give him as much as i can.