My mother appears to be hallucinating but will not see a doctor, should we try and have her committed?

My mother is 67 years old. She believes that my father is running around with other women, is going to give all their money away, is setting up a banking scheme that only one of these women knows how to do and the banks can't see it , and she says my father has these conversations with her telling her he is doing these things. etc... my father is 70 years old - not in the greatest health. He does not have these conversations with my mother. Mom does not think there is anything wrong with her. I think she is having hallucinations. She really believes that these things are happening and she is extremely agitated and upset. She verbally attackes my Dad and even me if I disagree with her. How do I convince her to go to a doctor? I have talked with her doctor(they tried to call her and tell her it was time for a check-up with no luck) Dad and I are on the verge of going to a judge and having her committed for evaluation. Is this the right move or should we continue to gently tell her these things are not true and try to coax her to a doctor?