Hello there!
There isn't much information you have here beside word count and general plot line, so should you consider me for the project I would ask we discuss over chat a little more specifically what kind of methods of stress reduction you're looking for, i.e. activities, exercises, mindfulness, etc.
You say one long, continuous manuscript is okay, correct? If there isn't any formatting or chapter outline requirements necessary then I can surely be able to write you 30,000 words of stress reduction management in 30 days or less. I will say 30 days just to be safe, but I will most likely get it to you sooner, if you choose me for the project.
I am also able to provide you a sample writing piece over chat free of charge if you're interested, that way you can decide if my writing suits your ideas.
Thank you for the consideration!