If it was dead I think you would have noticed things picking at it, etc. When my inverts molt they hide for a good week or so. Try to poke around with a flash light in the dark, you may have a better change of finding him crawling out after the lights are out if he feel vulnerable from a molt. Best of luck, im about to get my first porcelain this week.
Here's to swimmin with bowlegged women.
Reef with 30G Sump/Fuge Combo
-30G LTAnemonarium with mated porcelain crabs, 10 sexy shrimp, and 2 pink skunks all tied into the other 135G in my system.