Is there any life at all? If even a little bit, give it some time and maybe it will come back. You could try Neptune's Seawood organic plant food.

I had what I thought were some casualties from this past winter. Mine were evergreen azalea but two of them lost every single leaf and by Spring looked absolutely dead. Could not find any green on one when scratching, and was not sure but thought I found green on the other when scratching.

So I fertilized with Hollytone last week of April I think, and watered deeply for a few weeks. After three to four weeks one of them pushed out some new leaves down low on the main stem. (these were small plants to begin with - no taller than 18in). This one has continued to grow more leaves from down low so I will probably trim off the branches above eventually. The other azalea was dead as a doornail after all so I pulled and replaced with a new azalea recently.

Basically give it a month of good watering after you feed and then if nothing, you know its dead.