Hello there,
I have more than 1 year of experience in building responsive WordPress websites and online marketing.
I can recreate your original website into WordPress as it looks now or make it more user-friendly, mobile ready and beautiful. Since I don't know how many pages/posts and APIs there are on the website, I can't know how much time and cost It will take. I can explain those factors after I've seen the original website.
If your volunteers are untrained, I can also make an explainer video for them (in Hindi or English) about how to post new content on the website.
Thank You! Hope to hear from you!