Salaam ssbaig.
Venting is good. Helps us get it all out and sometimes that's the best thing to do before we tackle a problem.
Some people really don't like the idea of all the rasms. I know I'm not into it and I was lucky enough to have a fiance (now husband) who agreed with me and we avoided a lot of it.
But the thing is, we TALKED about it prior to coming to the decision of not doing anything but the simplest nikah and valima we could manage.
But other people, like you, like the idea of the all rasms prior to the wedding (and after the wedding ;)). And that's ok too.
So long as both sides are ok with it. You are. He's not. But here's what I don't understand. Why didn't you have this discussion a while back? Understand I'm not accusing you or criticizing. But it sounds to me like you've put quite a lot of time and effort into making your mehndi and all the other rasms the very best and if you and your fiance talk at all (which it seems you do), he would know about it. So why didn't he say anything about it beforehand? It's rather inconsiderate to watch someone put in all that effort only to tell them a few weeks in advance that you'll be having none of it.
You definitely need to talk to him. Explain to him that you've gone to a lot of effort and you've been working hard on this for a while so why didn't he say anything beforehand? Explain to him that regardless of his misgivings, everything is in the works now and to pull out now when so many people have put effort into it and are looking forward to it would be bad manners...it would make you look bad and it would make him look bad.
As for his demand that only immediate family be there for the nikah...that's a bit odd. That's usually the event that EVERYONE is there for. The other rasms...even the valima aren't really that big of a deal in people's minds as the Nikah itself. That's the event that everyone comes to see. And again, this is something that he was probably aware of a long while back. I'm sure it couldn't have escaped him that your family and friends would be coming from all over to see you get married. Why make such an impossible demand, and why now when you're literally days away from the big day?
Talk to your parents and discuss with them what they think is the best way to speak to him. And then speak to him. Soon. Something's up and it needs to be straightened out fast.
Also, that comment he made to your mom about her doing "chichora" things. Not cool. She's his mother to be. She's his elder. She is to be respected. He should already know that. Why he doesn't, I'm not sure. But sometime during your discussion, you have to make it clear in a calm and firm manner that such disrespect isn't to be tolerated.