yes, but they don't have to heal like that. Essential Dignity is a free heal that heals more the lower you are on hp. but i think they changed that to max potency if you're under 50%, so they don't have to let you get that low. however, so long as you didn't die, don't worry about it.

a white mage could wait for you to get low too before using benediction

but that's just min maxing. they could use essential dignity with lower potency. it's still free