I first noticed signs of trouble about a year ago. A small limb will droop, then the leaves on that limb turn pale, then brown. Eventually the small limb dies, then the entire larger limb goes through the same process. About half of two large shrubs are gone now. There are fungal diseases that pester azaleas here.
Symptoms are similar.
Phomopsis dieback, which is triggered by stress, causes wilting and yellowing foliage and dying twigs and branches. If you cut a stem of the plant and see brown streaks, Phomopsis is the problem. Remove any affected branches to try to control the situation. This may work, and with special care through this heat and drought, your plants may make it. Keep the soil moist but not soggy.