Mass. Gen. Laws ch. 201F § 2
A parent, legal guardian or legal custodian of a minor, by a caregiver authorization affidavit, may authorize a designated caregiver to exercise certain concurrent parental rights and responsibilities relative to a designated minor's education and health care, as described in section 3. If a conflicting decision is made under these concurrent rights and responsibilities, the decision of the authorizing party shall supersede the decision of the caregiver.
The caregiver authorization affidavit shall only authorize those rights and responsibilities that the authorizing party possesses and shall not divest the authorizing party of his rights or responsibilities.
The authorizing party shall not use a caregiver authorization affidavit to circumvent any state or federal law, solely for the purposes of attendance at a particular school, or to re-confer rights to a caregiver from whom those rights have been removed by a court of law.
Mass. Gen. Laws ch. 201F, § 2