Fiancè's family said they would pay for our entire wedding and the dress

Me and my fiancè can't afford my dream wedding. Honestly my fiance is a minimalist anyway and prefers a courthouse wedding because he's shy but he knows I want an actual wedding. I found the PERFECT dress and I can't even afford it. My fiancè comes from an extremely wealthy family. His family are millionaires. He distanced himself from them after college to get them to pay his college tuition and then distanced himself which got him cut off financially. He said to me that his parents were abusive and allowed him to be abused by multiple people and the least they could have done to make up for his trauma is pay his college tuition. His parents found out we are getting married and messaged me on Facebook offering to pay for the entire thing including my dress. His mom said all she asks is to see me in the dress. We could actually have our dream wedding. My fiancè is saying no. He hasn't been involved with his family in 6 years and doesn't want them at our wedding. He believes them paying for the wedding is them trying to find a way back into his life to hurt him.