User friendly CMS with ability make everything from a scratch

I have a simple question and need some suggestions.

I was asked to make a website, which further on will be maintained by the owner of the website. I have good knowledge about HTML, CSS and JS, and can make such website quite fast, but the issue is that the owner don't want me to maintain website afterwards and he wish to put some extra images on weekly bases, change some paragraphs and some other simple items, but he has no knowledge about any web development skills.

I would like to ask, do any of you have any ideas, what software or Content Management System (I have tried Word Press, but I did it seems like it is not a solution for me) I could use which would allow me to create website from a scratch containing ONLY my written code, but also allow have some sort of visual user friendly possibility to edit it?

Thank you for any suggestions.