:salam:
:bism:
You brother did a great job, but it is not usual for a non formally educated person in islamic sciences to write similar books as that books are primary sources of islamic knowledge and practice.
In my country a mechanical engineer translated Quran mashaAllah.
The maybe best way out is to add an author formally educated at a well respected islamic university to revise in depth the manuscript and add his contribution.
Please try to be kind and thankfull to everyone, especially women, as this is in our deen and it can make you problems if opposite.
The sister made a legit comment, but from other cultural and less erudite/academic background and anyways, your question is not that best suited for a forum.
You did a great work, but, what I think is really needed, is to try to compile a great dua book, to research, find out and write every single hadith dua, to index them and make chapters. That is very needed in English, as there are not a lot books like Hisn Al Muslim, and I think it will sell very good inshaAllah.
It would be good to research at least sahih and hasen hadith (I think there should be at least 100 000 hadith to research) from known and kess known hadith books.
It would be great to write duas with harakat, with beautiful font, to write their translation and stated benefits, like a part of narration "...benefits, merits...". Also it would be very good to write a chapter about etiquette of dua. This book I think should be at least 2000 pages long and split into parts.
There is a similar book in my language, about 600 pages, but not containing mere 20% of duas from sahih hadith.
After you write such a book, you could write a computer app and it would be a great sadaqah jariya for you inshaAllah.
It is a great project and you should try to make a team of at least 5-6 people, a good graphic designer/caligraphy writer etc.
Nowdays there are a lot hadith online, like:
https://sunnah.com/
And it is a lot easier with computer programs islamic libraries etc.
Most people know fiqh throught religious education and upbrining, but duas are a lot less known and practiced.
Another good idea is dhikr wordings and salawat wordings from hadith.