I don't suppose she has a living will or power of attorney put together that names her husband of 30 years? Actually, I would think if he wanted to push the issue spouse will always have say over children in making the final decisions. Although, in that position, I don't know if I could assert that power or not.
If you haven't done so, everyone get your documents together. First thing my wife and I did after we got married (well, after we consummated it...) was get to the attorney. Wills taken care of, Power of attorney naming each other and my best friend if something happens to us both together, living will saying "pull the plug," and everything going to a trust to be distributed to the educational pursuits of our young nieces and nephews (since we're waiting a while for children).
Nothing makes me happier than to feel like my family can't interfere with MY wishes on how I leave the Earth. In desperate measures, people do desperate things.