I'm really very sorry to hear this.
I feel a tinge of guilt because I said I thought the corals could withstand a 2 day blackout.
I really don't know what to say. I'm sorry.
I know about the dead coral thing. I can at least share a little of your pain there (different reasons - and still ongoing
I've given up on the tank in question - it's beyond fixing).
I really hope you get on top of this soon. I know the frustration of dinos, I had it twice, and nearly quit the hobby 100% both times. It's very demoralizing. I hope it resolves soon.