Moved from "Interview Experiences" to "General Topics". (It's not an interview experience
)
Did you qualify for FMLA? In terms of length of employment, etc? If you met the legal qualifications of FMLA, I would certainly think you have a case.
If it were me, I'd call my union every day until I found out either the arbitration date or the reason whey they're delaying. If they are dilly-dallying then I would get my own individual legal counsel and build a case not only against the company for denial of FMLA but also the union for failure of representation.