Mass. Gen. Laws ch. 12 § 2A
If the attorney general is disabled from performing his official duties, the first assistant attorney general shall perform the same during such disability. If the attorney general is disabled from performing his official duties and the first assistant attorney general is also disabled, the governor shall appoint one of the other assistant attorneys general to perform the official duties of the attorney general during the disability of the attorney general and the first assistant attorney general. In the event of a vacancy in the office of attorney general, the first assistant attorney general shall be continued in office and shall perform all statutory duties of the attorney general until an attorney general is duly qualified. In the event that the first assistant attorney general is disabled or is unable to fill the vacancy in the office of attorney general, the governor shall appoint one of the other assistant attorneys general to perform the statutory duties of the office during the disability of the first assistant attorney general or until an attorney general is duly qualified. The person upon whom such duties shall devolve shall notwithstanding anything to the contrary herein contained possess the powers and perform the duties of the attorney general only in matters not admitting of delay, but shall have no power to make appointments.
Mass. Gen. Laws ch. 12, § 2A