Okay, I have a boy who has been with me for almost a year. He will be two in January. For the last week he has been crying at drop off. It is because he is mad that his dad is leaving him. For the first couple of days I tried to comfort him, but he doesn't want anything to do with me, so I have been letting him cry at the door. However, it bothers the other children so today I moved him to a playpen in the next room as today's tantrum has now gone on for 20 mins. Well, he stopped crying after a few mins but when I went in to see if he was ready to join the others, he started up again. So, finally I moved him back into the playroom (I didn't want him to fall asleep in the playpen) but put him in the corner and told him when he was ready to join the others he could come play.
Is there anything else I can do, or do differently in order to help him calm down? He literally got himself so worked up from screaming that he was doing the gag cough, like he was going to throw up.

On a side note this boy and his brother (twins) have recently got into this little drama king habit where if anyone takes a toy/hits/ does something they don't like they instantly throw themselves on the ground and cry. Also, if something happens to one, the other generally joins the other one crying. Lol... Generally I wait until they have calmed down to address the issue as I dont want them to continue with this behaviour, but other than that I'm at a loss.