Caring for my disabled wife

I am an LEO of 9yrs. I have been caring for my disabled wife for over 4 years. Due to her illness she is hospitalized approx 10 times a year for a week or more. There are times I am required to come into work an hour or two late every few months to tend to her medical needs. I have done this for four years under 8 seperate supervisors. My current supervisor has informed me that I am a burden to my shift and that he can never count on me being at work, so he requested I be transfered from his shift. For the last 6mos I have only been assigned to a specific zone of the city that has no calls for service. Recently, I was advised that I am being written up for violating our city's leave policy and forced to work our front desk for the last 4 shifts as punishment for my caretaker responsibilities for my wife. The front desk is rotated between officers each shift. FMLA paperwork has been completed with Human Resource. I was advised by HR that since Im not the one disabled I have no rights