In the absence of an advanced directive, such as a will, living will or power of attorney, or preneed burial or cremation contract, after the death of the protected person, a guardian or a conservator, if there is no guardian, shall continue to have authority to make decisions regarding the body of the deceased protected person for the purposes of authorizing an autopsy and making funeral arrangements. The guardian's or conservator's authority shall continue until an executor or executrix or an administrator or administratrix has been appointed.