I don't know how they will bring Brady back realistically and I don't think they will incorporate the supernatural aspect of the book.
I could see Brady with some form of brain damage that makes him think he has some sort of supernatural powers as a reference to the books but that's it.
There are only 3 directions it can go:
They adapt the second book. Whole new story, no Brady (or at least conscious Brady).
They skip to the third book. Finish the Brady story arc.
They invent a whole new plot for Bill to investigate.
I suppose the first two options depend on whether the rights are available from King or not.
Looks like they found a way to wake him up! ( greedy doctor giving him experimental drugs to enhance his brain).
We're on episode 2 and it seems that he's in telepathic communication with one of the nurses. Was it in the book? Does he actually get powers?