Massachusetts law permits individuals to leave instructions as to their final wishes--that is--their preference as to funeral services and disposition of their remains. The only requirement is that the instructions be in writing and signed before a witness (239 C.M.R. § 3.09(b)). The writing may designate who has authority to take possession of the remains. In the absence of such a writing (or, if the person designated cannot or will not act according to the instructions), authority over the remains belongs to (in order and if applicable):
the entity with which the decedent signed a pre-need funeral services contract
the surviving spouse
adult children
parents
siblings
a legally appointed guardian
any other person authorized or obligated by law.
If you are planning your estate and you are comfortable addressing these matters, it makes sense to include a Disposition as to Remains as part of your estate plan.