Allowing students (kids) use parent email to login in laravel project

A Parent wants to apply for his/her children, who are a minimum of 2 years old, in an educational institution. The students(kids) don't have email and thus parent's email is used for the students. Question: how to login the children using the parent's email using the same login form? Note: Currently, I have separate login and registration forms for each ( student and guardian) which I am merging.

via Chebli Mohamed