The child just keeps on crying and will not stop

What do you do with a young child who just keeps crying and you can not get them to stop? This was a recent question and I was around at the time so I could see the whole part rather than just taking the mother's word for it. The mom was stressed and in a hurry as she whisked him from place to place as she tried to get everything on her list done. he was stressed, tired, it was past his morning snack and normally he would have been resting a little bit before a quick nap. Instead he was not home or at his child care so the environment was different as well. Surprise, he was cranky. He would start to quiet down a little bit until him mom looked at him and then he would break out in more loud crying. Interestingly he was having a hard time manufacturing tears. That is a good sign that he is more mad than anything else. After 15 minutes of battle, mom pulled out his blanket and laid it out, gave him a soft toy, talked quietly with him for a minute and gave him a cookie. Before the cookie was 1/2 gone he was a sleep and she had 30 minutes that were uninterrupted to finish what she needed. He was being what he was supposed to be. A two year old.