Manual Login for a WP site inside an iFrame

I developed a Learning Management System based on LearnDash.
My client need to insert this WP site inside an iFrame for a biggest portal developed in SharePoint.
The big Sharepoint portal has a registration and login working.
My client needs to use that login and registration for login to my WP site.
Each time a user logs into the big portal, I need to do 2 things:
1. If the user isn’t registered within WP site, I need to register the user manually
2. Log in the user to work with the LMS courses
Each time a user logout from the big portal, I hace to logout the user in WP.

Any of you knows how to do that?
Thanks