I have in mind my own case, when the author has neither a scientific degree, nor a scientific supervisor, but there is a scientific material in the form of a Preprint Математические заметки о природе вещей
Yes, it is possible to to get a grant to write a book even when the author has neither a scientific degree, nor a scientific supervisor. As I see it, you have to inform the publisher of your intention. Then, they will ask you to send a book proposal. If they find it interesting, they will send it for a peer review system. If reviwers agree on the publication, then you can aply for a grant to an appropriate funding institution.
Thank you, Orlando. So, the first step is the choice of a scientific publishing house and the submission of an application for the publication of a monograph. As far as I understand, the choice should be made in favor of the English-speaking version of the book. However, I'm afraid that any solid scientific publishing house will simply laugh at my intention. Yours faithfully, the author.
I you suggest I timely topic and you proposal is written in a clear and clean English, I do not find any reason for the Publisher to laugh at you intention. Of course, when one submits a paper or a book proposal we should hope the best and antecipate the worst. When we think so, we are prepared to not become frustated in the case of a rejection.
Honestly, I'm not afraid of a motivated rejectionl. However, it is difficult for me to take the first step, because I think in Russian, and for translation into English I use a computer translator, and therefore the necessity of publishing a book will be difficult for me to justify before the publisher. However, we must try.