Sorry dude but he certainly pulled them, both times. I was nice the 1st time. The 2nd time he was closest and his gun heal triggered it. He immediately had 2 elites, 3 strong, and a few trash all attacking him at once. I only have single taunt at level 19. He went down in seconds.
If everybody's outside of aggro range a heal will not pull. When someone goes afk sometimes I'll put an AOE heal directly under a group of mobs for the chuckles. They do not pull.
However, if someone (not necessarily the healer) facepulls or arsepulls WHILE the healer is healing, the healer will get aggro immediately. This causes a disproportionate amount of healers to be blamed for facepulling, since they're always the first to die. If he was closest he probably did the facepulling and his healing at the same time just sealed the deal.