Hi, 

Yes, unfortunately it is dead. When a plant is this far gone with out leaves, it is difficult to determine what the cause of decline was. 

A common problem to Japanese Hollies is a fungal root rot called Thielaviopsis basicola or more simply Black Root Rot. When conditions are favorable for the fungus it can infect susceptible plants. Some conditions that it needs to grow are: poor drainage, cooler soil temperatures, higher pH or soil acidity, and nutrient levels which are either poor and too low or too high and may contain too much Nitrogen (from fertilizer). Japanese hollies are sensitive to these conditions. 

There is not treatment or cure Black Root Rot for homeowners as any registered fungicide would need to be applied by a licensed pesticide applicator and the cost doesn't typically warrant control. You would also need to proactively treat before the plant was infected and long-term use of fungicide has proven to be harmful to beneficial insects and can disrupt naturally occurring soil microbes.

You can remove the plant and try another boxwood for a similar look. Boxwood come with their own set of common problems but tend to be more resilient if pruned properly. (Yours looks like it has some leaf miner damage-very common). 

Let us know if you have further questions. 

Emily