Getting rid of the JW "carers" is probably the best for him although given his situation, change is very hard to go through.
If he is going to have carers, it will be such a relief to him if they simply do the work they do with no religious guilt and overtones attached.
I really feel for you and your brother Pale. This is hard and I know you feel love and protectiveness towards him.
It is most likely that his life is going to be far better once this all gets sorted.