How to give an user access to view (not edit) a single page

I have a site for a medical analysis laboratory and they need to give the patients private access online to view their results and download the results as pdf.The patients will be given an access link, username and password, and they will get to see only the page with their own results. They will not have access to wp-admin area, they will not edit anything, just view a page and download a file.

Is there some way I can get this done? Is there a plugin or some other way I can do this?

Thanks.