I don’t think you are under any obligation to use their form. Check out Five Wishes - here is the wiki link & there are links there:
https://en.wikipedia.org/wiki/Five_Wishes
A lot of hospices recommend/use it and an ombudsman suggested it to me and gave me copies for someone I was caring for who was terminal.
Here’s one link to the form:
http://positivehealthcare.net/wp-content/uploads/2014/04/Five-Wishes-for-Website_PHP.pdf
Per the Wiki link:
According to analysis by the American Bar Association’s Commission on Law and Aging, Five Wishes currently meets the legal requirements for an advance directive in the following 42 states [SEE list at wiki link] and the District of Columbia. In the remaining 8 states, (Alabama, Indiana, Kansas, New Hampshire, Ohio, Oregon, Texas, and Utah) a statutory form is required, and one must attach the state document if one wishes to use the Five Wishes document as a guide.
That is the one the hospital here uses.
I think that there are other forms, I have my own lawyer drawn up document
However the unthinking and innocent may end up using this form, that is being pushed by my primary care via obamacare.