Same problem with companion dying in water in the harpy fight. Resurrect spell unable to target companion because of location.
Another problem in same fight: before he was dead, downed companion in water kept standing up (with help) and insta-dropping, even with a big heal. It happened three times, apparently without any new enemy damage.
He would stand up with the groan sound. Heal would succeed and he would show half health, then, before he could take any action, he'd drop down again.
Eventually he ran out of saves, the enemies killed him, and he couldn't be targeted to resurrect.
As mentioned before, the game was unplayable without a reload to prior save.