dr. eric mcdonald and his wife seemed like an especially happy couple today. ♪ if you're happy and you snowr: certainly a lot happier than they were four days ago. >> every father's worst nightmare. >> reporter: it was around 6:30 at night last thursday, one of the hot days of last week's heat wave. mrs. mcdonald in her car with their 1-year-old son, james, dr. mach donald in his son right behind them. when suddenly mrs. mcdonald their son had become almost completely unresponsive. she pulled over to the side of the road not far from their waldorf home, and just before her husband pulled up started giving her son cpr. >> i tried to blow in his mouth and see if he start to breathe again. >> reporter: it turns out james had a seizure brought on by a high fever. >> probably the most terrified i've been as a parent or as a physician. >> reporter: a situation made worst by the scorching temperatures outside. according to james' father, the chairman of emergency services at southern maryland hospital center, knows a thing or two about medical emergencies. >> i've been an e.r. doc since 2007. >> r