The fact my step son decides it's OK to work him self up by crying and to play with his food and…

The fact my step son decides it's OK to work him self up by crying and to play with his food and then get punished and decide its OK to just throw up all over his food is beyond me. I definitely HATE his birth mom for keeping him an extra week. Not only did he miss a week of school but he missed a week of his medicine too! So now his body has to readjust to it. I'm so over her selfish ways! I don't see how parents can be so selfish!