My history with sponges is varied.
If it's a sponge that forms under a rock, it may or may not recover. I've seen them survive even after being exposed to the air. And they tolerate fairly dramatic shifts in water parameters as often as not.
If it's a decorative sponge that grows in the light, once they start to deteriorate there is very little hope of stopping it. They almost never survive even very short exposure to the air. And they do NOT deal well with dramatic water parameter changes.
But that's just my experience with sponges. Other's may do better or worse.