Reef Turned White Please Help with Suggestions!!!!!

My buddy's got a 55 gallon Reef tank with a 29 gallon sump. Last night at
2am when he went to bed, everything was fine. Tank was Crystal Clear. This
morning 6 hours later, his tank was completely white, u couldnt' even see
inside the tank AT ALL.
All his fish, except two Perppermint Shrimp are dead. Everything died, 6
Blue Chromis, Maroon Clown, Purple Tang, Harlequin Shrimp, Emrald Crabs,
Cleaner Shrimp, Fire Shrimp, Electric Scallop. Everything!!!
The Corals seem to be opening up now alittle but what the hell do u think
happened??
Like I said, last night, Everything seemed to be fine, six hours later
Disaster.
He just started working at a LFS a couple months ago, and he "had" to goto
work this morning. I am going to take him up a water sample asap so I dont'
have any reading at this time.
Any Ideas, help, Suggestions. And Since EVerything died, I assume getting
the Coral Outta there asap would also be Vital.