I have 2 Medium sized Azaleas in pots in my garden planted last year. One is doing really well and flowering again. The other
one looks as if it is dying. They were bought together and have been treated exactly the same. What is happening to the one that looks unhealthy, and what can I do? Both are in the same special compost in large enough pots and are in the same position.
I can't really say from just your description.
This article may help.https://www.gardeningknowhow.com/ornamental/shrubs/azalea/azalea-plants-in-pots.htm
You can upload images, and it may be of more help for us to see the plant.