It would be a difficult decision. My mothers living will/medical directive has a full paragraph on how she understands the burden I wouold face regarding care and life support and how the document is designed to alleviate the burden of what the decisions should be. Her wishes are VERY specific, what antibiotics to use, when to use a ventilator, how long to be on a ventilator, specific measures that can and cannot be used, even who can visit her in the hospital. I was suprised at how specific it was. I also have full medical power of attorney should anything come up not covered, but I would be suprised if it did, the document is several pages and covers everything from alzhiemers to car accident.
It was a little morbid for me to read, but it is also comforting to know she thought it out and is very specific as to what she wants.
WOW -- was that a document that was given to her already prepared, or did she dictate her precise wishes? I can see now that what I thought were clear wishes have to be amended .. dear God. I would love to know exactly what it says, if you would not be opposed to sharing ... that's mind boggling.