Peoples views on Evangelical Marriages?

My 21 year old son is due to be married, he dated the girl for over a year and recently got engaged, within 1 week he announced in a couple of months he was getting married. He continued the marriage would be in an evangelical hall and the marriage carried out by a member of the church getting a special licence. I have difficulty accepting this as I have another beleif, although I am not religious. My view is marriages should only be conducted by a minister and refuse to accept a lay preacher with a special licence. In conclusion I have said I will not attend his marriage, which saddens me greatly, and I will not accept the girl, who is a fantastic person as my daughter-in-law. Would people please advise, this a very serious issue.