There are two issues going here:
(1) The recording is LEGAL if your husband recorded it
AND he was part of the conversation with you. In
other words, no third-party recorded you having
a conversation with hubby.
(2) Medical Marijuana use (MMJ) FOR medical purposes
would be covered under HIPAA as any other prescription
drug would be covered. So . . . if Doc discussed with
anybody else but you . . . YES that would violate the
"spirit" of HIPAA. You however cannot sue under the
HIPAA code (no private action or lawsuit). You report
the good doctor to the Michigan State agency that
oversees HIPAA [in Lansing, MI].
(3) BONUS ROUND! Do you have a possible lawsuit against
Hubby? You might under: a) "invasion of privacy," and
"defamation" as he put you in a "bad light" (with doctor)
causing you damages (loss of the MMJ card). Did you GIVE
PERMISSION to Hubby to discuss your condition with the Doc
or anyone else? If NO then it's a GO! -----Good luck!
THIS ANSWER IS PURELY FOR ACADEMIC DISCUSSION ONLY AND DOES NOT CONSTITUTE ANY TYPE OF LEGAL ADVICE OR LEGAL REPRESENTATION.