A guardian is different from a caregiver because when a child has a caregiver, either the caregiver or the parent can make decisions for the child. When a child has a guardian, only the guardian, not the parent, can make decisions.
The form is also called a "Caregiver Authorization Affidavit." The form says you are sharing medical and educational decision-making power with the caregiver you name. You can find instructions from the Massachusetts Probate Court on how to fill out the form.
The Family & Medical Leave Act (FMLA) and the California Family Rights Act (CFRA) both can provide protections to caregivers, such as leave of absence and claims for interference with these rights, as well as claims for retaliation against exercising rights to FMLA and CFRA leaves.
A Caregiver's Authorization Affidavit is an official form based on California's recognition that adults who have minors living with them are “caregivers” who often want and need to take some responsibility for the minor's education and other care.