This is quite puzzling, Hunter. We need more information to really come to a conclusion. I have a number of articles that have ideas but I wonder what YOU have noticed going on over time. Is this sudden? Has drainage changed? Has a large tree which might have shaded the shrub gone away and it is basically getting sunburned? Also,  do branches snap or bend?
Here are some ideas others have had: https://ask2.extension.org/kb/faq.php?id=610876 or https://extension.unh.edu/blog/2018/02/how-can-i-help-my-holly-bush-brown-leaves-dead-branches-it or https://www.pennlive.com/gardening/2012/03/dying_hollies.html and one last: https://plants.usda.gov/DocumentLibrary/factsheet/pdf/fs_ilop.pdf
Once you have looked at these other ideas and thought about changes that might have occurred, write me again and we will see what is the best course of action.