NOT fire blight! That does not affect rhododendrons/azaleas. It looks like a combination of too much heat and dry soils. Despite how other nearby plants are doing, the root system of that plant may not have been up to the task of supplying what it needed.....it happens.

The green under the bark may mean nothing. Even very dead plants can hold a lot of moisture in their tissues that remains 'green' for an extended period. I'd cut the plant back and keep it well watered for the rest of the season and see how it looks next spring. With that much brown showing, I wouldn't hold out a lot of hope, unfortunately.

Rhodies have shallow roots, and so removing all nearby plants and mulching will help prevent this type of issue in the future. Water well, and check that the soil in the rootball as well as the native soil are moist without being soggy.

is this a new planting?

NHBabs, It was about 5 years old. I purchased it when it was in a 1 gallon pot and it reached 4' from that time to now. It was doing well and had a nice flowering this year.

I did find out what the problem was and as gardengal said, it was not fire blight. I brought pictures on my phone to the cooperative extension and they said it was root rot and pointed out all the features that confirm that diagnosis for them. Besides the leaves staying on the shrub, the bark on the trunk peeled away easily and the cambium had turned an orange color. They said if I were to dig up the plant I would find that the soil around and deep into the root ball would be moist and the outer layers of the roots would peel away easily too. Sure enough, after digging up the plant I found this to be the case. I was told not to put any other shrub in that area and to dig out as much as the soil in that area and the surrounding area and dispose of it. Then fill the hole with new topsoil and amendments and don't disturb the area further. Also, they stressed the need to clean equipment and avoid walking all over the rest of the garden if I got some of that soil on my shoes. They said that I can add fungicide to the soil but there is no guarantee that this will get rid of the disease. Since I live in an area where the soil is sandy drainage was not the problem but they think between the excessive heat and the fact that we were getting downpours in between, and I was watering at night to make sure the plants didn't die in the heat that the plant might have gone over the edge with too much of a good thing. I don't think it helped that I also fertilized right after flowering and the plants suffered some light fertilizer burn but nothing major, about 2 months before this. In any event they seemed to recover quickly. I was also advised not to fertilize in the future and the only thing I should be doing if the plants start to look strange, like light colored leaves, was to have the ph checked. Sure is going to look strange without a plant in that area in the future. Looks like I'll have to get creative and add some kind of ornament in that area to balance it out.