The patchy dieback shown in the photo does not appear to be caused by drought stress, though we cannot rule it out. Was the shrub (it looks like a Japanese Holly) being watered periodically this past summer? Japanese Hollies can be vulnerable to a root infection called Thielaviopsis, for which there is no cure. Drought or other stresses could also predispose plants to Botryosphaeria canker, a fungal infection which is similarly untreatable. All you can do is to trim out the dead wood and wait for regrowth on the surrounding branches to fill back in, which might take a few years, depending on the size of the gap. If the shrubs were over-watered or are growing in soil that isn't acidic enough (as determined by a laboratory soil test), then Thielaviopsis may be more likely; if under-watered or pruned heavily in the past, then Botryosphaeria might be more likely, though in the latter case we'd expect to see dead leaves still clinging to the branches.

Monitor the plant for watering needs since Maryland is still in significant drought status and evergreens going into winter dehydrated are more likely to suffer dieback or to be killed. Our Watering Trees and Shrubs web page provides guidance. The stone mulch and presumed landscape fabric underneath it may make it hard to probe for feeling the soil moisture level several inches below the surface.

Miri