Your post is intriguing, but a bit confusing. Are you that doctor who recovered, and is not a good writer? If not, I'd be curious what your relationship to this doctor is--if you care to share.
I agree with
@Wayne here. It is unclear if you are the doctor or your are asking on behalf of the doctor?
Book writing isn’t easy, especially for anyone who has any sort of disability. I speak from firsthand experience. There are quite a few writer tools these days that can help, but when you get right down to it, you are the one who has to write your book.
And I agree with
@wabi-sabi, the Ghostwriter is a great option for those who are not proficient writers. They work in various ways depending on the induvial Ghostwriter or the requests of the author. They can write your entire book from you verbally dialoging, even just ideas or facts. They can write your book from notes you supply them, and many other options.
If you wish to write your own book, it is best to do so in your native language. Trying to write a book in a secondary language that is anything less than absolute master level won’t turn out well. The book can always be translated by a professional after the fact to another language.
But if English is your first language and your skills at writing are less than comfortable, a Ghostwriter is really your only option for writing a book. Be prepared though because Ghostwriters tend to cost a pretty penny. Actually, the more work others have to do on your book, the more money you should be prepared to dish out, and you might be surprised at just how much those bills add up to in the author and publishing realm.