Clear as Mud?
I'd been tempted to consider reluctance by bishops to provide clear moral guidance concerning end of life medical decisions to be a function of wanting to avoid controversy.
After all, Pope Paul VI gave us Humane Vitae (a heroic act for a man who was, by nature, not confrontational), and there is the opinion that he never wrote another encyclical because of the reaction to HV.
But after reading Tom's post, I guess it must be a prudential matter... although I'm leery of comparing burdens and benefits given that "burden" is such a highly subjective term. Reminds me of the "health of the mother" clause that pro-aborts hide behind; if the mother has a headache that's reason to end a pregnancy.
Even for those with the best of intentions weighing how burdensome something really is can be difficult. And for scrupulous souls it must be especially trying.
Update: To clarify my confusion: the burden of the caregiver is irrelevant, it is the wish of the patient, to the extent that can be discerned. And if it can't be then it's a simple matter of "erroring" on the side of life.
Zippy's comment on Disputations says: "Being a charity case is one of the most difficult vocations out there, but it is also one of the most spiritually rewarding to all involved."
Henri J. M. Nouwen gave up his writing and thinking career and for the last five years of his life severely disabled patients. When asked why he gave up so much he said "because they give me so much".
So, in 'opposite world' (as my wife refers to the world view of Christianity), the notion of 'burden' is problematic. If you are the patient you could look at the burden on your caregivers as a gift.