Mil’s questionable drinking habits

Hey everyone! There’s something I’ve been thinking about a lot and am having a hard time figuring out what to do. My future MIL is a mildly heavy drinker. She doesn’t necessarily take shots or drink hard liquor but she drinks A LOT of beer. She’s said on more than one occasion that she plans on getting wasted at our wedding. Her reasoning behind it is “why wouldn’t I?? It’s my sons wedding!!” As if that type of joyous occasion warrants her probably not even remembering it. If she could handle herself, I wouldn’t really mind. But the more she drinks, the more she’s convinced that people are against her and she’s more likely to be loud and easily argumentative. I really don’t want her to make a scene (or several) at the wedding, she’s prone to doing so even in casual situations. I’ve already told her how the bar is only paid for a few hours and after that everyone would pay their own drinks (wedding is an early afternoon Sunday event). She says she’s going to take the next day off of work, carpool with someone, and get a hotel nearby because of how much she plans on drinking. However, I almost regret telling her about the bar so that she would be forced to not get extremely drunk. I’ve brought up my concerns up to my fiancé and he kind of just sighs and says “yep, that’s my mom. That’s kinda how she is” as if he’s completely unconcerned. Am I being crazy? I feel crazy. But also, she’s the only person who is like that. None of our other family members really drink heavily or get crazy at parties. Please give me advice or let me know if I’m being way too dramatic😭