I was wrongly suspended for 3 days from work. My supervisor called my sister at her job and ask her if I had spoke with her, she said no.
My supervisor told her she knew I had been to the Doctor and wanted to know if I had issues at home. Is it legal for my supervisor to disclose personal information to my family.

Is it legal? I don't see any HIPPA laws being broken. Your supervisor just wanted to see if your sister could shed some light on your problems.

Why were you suspended "wrongly" for 3 days?

Agree with Twinkie - all else aside, why were you suspended and how did your Supervisor know how to contact your sister?