That's another way in which Croakamancy is a weaker branch than most, as compared to the way a Dirtamancer or a Dollamancer can heal their Golems. Still, I was thinking that maybe she could get him some sort of life draining sword, to restore him as he damages the enemy.
Uncroaked units, though, cost no upkeep. They are maintained by burning the Stuff of the corpse. While we haven't been told, I would wager that golems do cost upkeep, or, in the case of the Snow Golem, require a magic item, to be used continuously to maintain them. So, I think it's a bit more balanced than it may appear at first glance.