K's teacher ended up having chest pains today. They had to call an ambulance to have him transported out. The children were moved to the library, but they saw their teacher wheeled out. It greatly upset them all. At the moment, Mr. H is undergoing testing and is currently admitted to the hospital. I'll update as I know more.
ETA: He's out of the hospital with no heart attack, though he has lost one brother to a heart attack years ago. He's still not back in class yet, but anticipates returning by the end of the week. The kids miss him.