Coastal Leucothoe problem
Leucothoe prefers woodsy sites and frequently do not do well in the usual home site. It is hard to get them established. Check the base of the remaining plant to see if something might be digging there. Pick off the affected leaves. Check for any other abiotic problems. Actually the remaining one looks pretty good for a leucothoe. Keep it well watered if there is not an inch of rain in a week. https://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG86%20Common%20Abi... vw
It is underneath the canopy of a dogwood on the north side of a two story townhome. Is that woodsy enough?
It may be. We hope so. What it really likes are woods that have been woods for years and have not had townhouses built in them. vw