I'd guess the healer healed him whenever he lost a sliver of HP. It's pretty obvious in such cases, also, the tank can see whenever he gets healed as well. Doesn't always have to be a parser, really, though it's of course also possible to see it that way. Plus, you can see what which party member casts by looking at the party list. Though that one's a bit more dangerous since you might miss something important while you monitor the party list...