Hello,

There are a few diseases and pests common to junipers. The symptoms of disease and/or pest that I am seeing in the picture are whole branch dieback beginning at the ground level. But, I can not see a close up image of the foliage, the individual branches, bark, or the roots. In fact, the most accurate diagnosis of evergreen disease needs to be made by a plant lab where the infected plant tissue can be inspected by a plant pathologist.  

The C. Wayne Ellett Plant and Pest Diagnostic Clinic (PPDC), run by OSU, can examine samples of the tree(s). The samples can be sent through the mail, or hand delivered. The PPDC is located in Wooster, Ohio. I have listed a link for their website, last in the list below. The website gives the information needed for taking the samples and submitting them to the Clinic. You may also contact them directly with any questions about submitting samples.

The one disease that might be considered, is Phytophthora root rot. This disease is caused by the development of fungal-like organisms in a waterlogged root system, due to poor drainage conditions, along with excessive rain, watering, warm temperatures and heavy clay soil. But again, this is by no means a definitive answer. I mention it because if you or your friend decide to submit tree samples to the PPDC, it would be important to send in root samples.

I have listed several links for articles below with information about junipers, their diseases and pests, and also with information about Phytophthora root rot. 

Any suggestions for remediation or treatment would have to be made after the plant problem is diagnosed by a lab. 

Please write back if you should have more questions. 

Thanks for asking Ask Extension.

Betsy B. - MGV

https://hgic.clemson.edu/factsheet/juniper-diseases-insect-pests/

https://apps.extension.umn.edu/garden/diagnose/plant/evergreen/juniper/needlesyellow.html

https://plantfacts.osu.edu/tmi/Plantlist/juniperus.html

https://hortsense.cahnrs.wsu.edu/fact-sheet/juniper-phytophthora-root-rot/

https://sites.udel.edu/planthealth/tag/phytophthora-root-rot/

https://ppdc.osu.edu/