I'm currently out on FML. My medical condition was disclosed to my supervisor via email, without my permission. About two weeks later, my supervisor called me and left a voice mail message, saying, "I realize you didn't tell me, but do you want me to tell individiuals who were inquiring about my absence, what my medical condition was".
It's not unreasonable for your supervisor to know about your condition but there's no reason for your supervisor to share that information. Your supervisor should not be calling you to ask such ridiculous questions.