Marrying someone older than your parents

I am Nigerian living in the UK, my fiancé is older than my parents. We got together for wedding preps and my fiancé called my parents by their names. My dad nearly had a fit! He said that if he is to support this marriage then my husband to be has to give him the respect that he deserves and call him dad. My husband to be is refusing to because he is 55 and 5 years older than my father. I mean I can understand my fiancé’s plight and how odd he might find it having to call someone he is older than “dad” or “mum”... that’s okay for the English way of life but in Nigeria, we love respect a lot so my parents feel like they deserve to be respected and not being parted on the back while saying “hello Mike”- random name used as example. How do I settle this deference 😩