Should husband wear a kippah to a Jewish wedding, despite being 100% Christian?

My husband’s sister is marrying a Jewish man in a synagogue in a traditional Jewish wedding. We are Christian, my husband was raised Christian. My mother in law is insisting that my husband wear a kippah to his sisters wedding. He feels uncomfortable because that doesn’t represent him whatsoever. What do we do?

Edit: Thank you all for the prompt response!! I will talk it over with my husband and show him your responses. I didn’t realize it was a sign of respect and not a sign of being Jewish. He has zero problems with the Jewish faith, he just didn’t want to be portraying something that he is not.