Help figuring out bush issue

I believe these are cistena purple-leaf sand cherry bushes. They're all three about 12-13 yrs old. I let them grow taller in the summer because they hl block the sun/heat from coming in.

As you can see, one of them isn't like the others. Any idea what's going on? I included pictures of what might be some kind of fungus around only the base of the sick bush.

Appreciate any help to save this bush.