My Rhododendron appears to be dying
The photo attached is of the Rhodedendron I wrote about a few minutes ago.
Certified GKH Gardening Expert
Does that garden bed allow for drainage? If it does, and you just receive large amounts of rainfall, then you will have to put in counteractive ingredients for a fungal infection.
You may have a hard time finding the ingredients in your country, although they are completely safe, and better than the readily available alternatives. They can be ordered and shipped for reasonable prices, still.
Just apply a handful of DOLOMITIC LIME, and a tablespoon WETTABLE SULFUR per plant. Apply evenly around the plants root zone for the best results. It helps to do this once or twice per year if you know that it will remain wet in your area for long periods of time.
This article will give you more information on the care of these: https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/rhododendron-care.htm