It's a good argument. But it isn't a slam dunk, and the judge's decision won't necessarily turn on that argument. He has other tools to justify whatever outcome he wants.
Check out the Browning case ...
http://www.freerepublic.com/focus/f-news/1380586/posts?page=217#217
The statute says that any document which follows this model (XXXX) must be considered prima facie valid. The document in this question does not follow the model. I would highly recommend that Ken talk to a lawyer about what needs to happen to ensure that Mae gets a jury trial if the issue of the living will comes up. A judge might not consider the deviations from statutory language to be valid, but a jury almost certainly would.