My mother (whose autobiography is linked at left), commenting on a post about Terri Schiavo, writes about her own experience working with similarly disabled patients. I have met one of the patients she mentions and can attest to the inspirational quality of her life; she has an incredibly strong will to live.
I am a cognitive therapist who has worked with post head-injury patients for the past 14 years. I worked almost daily with 2 quadriplegics, one of whom had a brain-stem stroke, is tube-fed and has virtually no movement except eye blinks to communicate. Both of these patients are living amazing lives of ministry to others. Both are able to exhibit joy and to communicate their wishes. Terri can be taught to communicate.
The problem with "living" wills is that they rely on healthy people to project how they will feel is they later have a catastrophic illness. The will to live is so profound that we cannot possibly know that we will not want to live under even the most appalling conditions. In many many cases, it looks worse to you than to your dear family member who is laying there. And, having the power to snuff out the light on that person, a believer would have to wrestle with God's will, i.e, "Choose life, that she may live." Terri has so blessed the lives of those near and far. Her parents can be very proud. I would gladly volunteer to help her, if permitted.