Here is the problem--Florida Statute 765 makes up your mind for you in case you forgot:
765.401 The proxy.--
(1) If an incapacitated or developmentally disabled patient has not executed an advance directive, or designated a surrogate to execute an advance directive, or the designated or alternate surrogate is no longer available to make health care decisions, health care decisions may be made for the patient by any of the following individuals, in the following order of priority, if no individual in a prior class is reasonably available, willing, or competent to act:
(a) The judicially appointed guardian of the patient or the guardian advocate of the person having a developmental disability as defined in s. 393.063, who has been authorized to consent to medical treatment, if such guardian has previously been appointed; however, this paragraph shall not be construed to require such appointment before a treatment decision can be made under this subsection;
(b) The patient's spouse;
The only state which does not allow dehydration death via surrogate, is Illinois.