It sounds like his medicines are on the right track as far as the ones I recognize. Some of them I am not familiar with.

One thing to understand about myasthenia gravis is that stress sets it off. He most likely needs to take it easy for a while. Rest and rest some more.

The immune suppressive drugs such as immuran and prednisone take a while to kick in.

If he has a tumor in his thymus, removing it could help. They would need to do a cat scan to find out about that.

I am not sure that anybody really has all the answers in the US or other places.

I hope your Grandfather gets better.