Job Benefits Employer Won't Remove My Absentee Spouse from My Benefits

My question involves labor and employment law for the state of: California

Thanks in advance for any advice. I am inquiring on behalf of my younger sister. She works for a grocery store chain in California and is a member of the union. She is married and has had her husband covered on her medical, dental & vision insurance. After the last couple of years of an abusive marriage he split. Nobody knows where he is, she has no contact with him. During open enrollment she attempted to remove him from benefit coverage. She was unable to do so. She scheduled a meeting at the union office and they asked her to write up a statement of facts and sign it. She is asking that they remove him and stop taking money from her check for his coverage. The local union office sent the statement in for review and she received a letter asking for more information. She mailed a statement explaining that he has left and that she has no idea where he is. He is on Social Security Disability and I would believe is qualified for medical coverage through Medicare. She included that in her letter. They have once again denied the removal and state that they will continue to deduct from her check for his coverage. There is no evidence that he has attempted to use the coverage since he left (she would have received a statement).

Any ideas?

Job Benefits Employer Won't Remove My Absentee Spouse from My Benefits