The Palm Beach Post in Florida is reporting a case that is similar to the Terry Schiavo case of a few years ago. Both cases involve a young woman who has become incapacitated and did not leave behind written instructions regarding her wishes for medical care in that circumstance. These instructions are often referred to as a living will or a life support statement. Both cases also involve family members who can't agree on what decisions to make.
In Massachusetts, a living will is not a legally binding document. Every person over 18 in Massachusetts should have a Health Care Proxy which is the legal document appointing someone to make medical decisions for you in the event you are unable. In addition to signing the health care proxy, you should let your health care agent know what you wishes are for medical care, and writing down those wishes is often the best way to make sure they remember your wishes in the moment of crisis. Writing down your wishes also lets your other family members know that your agent is carrying out your decisions, rather than making their own.
A health care proxy and living will are usually part of a standard estate plan, but you can also obtain them from your doctor.
Thanks to David Goldman of the Florida Estate Planning Lawyer Blog for his post on this subject. Keep in mind that the rules regarding health care decision making, and the documents which govern that decision making, vary from state to state.