Hello
I just saw your post. I collect 慰問人形 and related items. ヘロヘロ and 文化人形 were types of dolls that were often used as comfort dolls. This is a link to a blog post I wrote some years ago - looks like I never did the follow up post. Oops. Since then I've collected about half a dozen dolls that are definitely imon ningyo - and others that I couldn't be sure about. They will often have the name of the person who made them written on them,.
Ikuko Miyazaki's Dolls (Imon ningyo part1) You won't find information in books on Japanese dolls and the article I cite in the blog post is the only thing that I know that has been specifically published about them in either English or Japanese. I haven't continued with that blog but the contact info is up to date if you want to ask me more about them - in case I forget to come back here!
Jan