This situation is not about the wedding at all. It's about two people with big cultural differences who need to have some serious communication before they get married. This is right up there with marrying someone of a different religion, ethnic group, or political persuasion. You have to work those things out before the wedding and get on the same page. If she is set on a big wedding and he isn't, somebody has to give. If he's willing to pay for it all AND go for the huge over-the-top wedding, then it's a match made in heaven.
For a large part, I totally agree with this.
I still cannot believe the issues that come up with my half Korean husband, or rather his mother. Someday I need to send a gift to his aunts back in Seoul and Busan, because they have calmed my MIL down many, many times. I'm still not "the perfect Korean wife" (b/c I'm not Asian at all), but her sisters have reminded her time and time again that I'm a good person, woman, mother, and wife, even if I don't call her Every Single Day just to make sure she's still breathing.
The cultural issues, when the parents are from another country, cannot even be counted, they can be so high in number. YES there are some families that assimilate to American "culture" immediately, but I haven't met any yet.
My MIL and FIL never had enough money, due to his hijinks, to help anyone have a big wedding, and their daughter actually snuck away to marry her ex...active heroin user and felon she met while counseling in a halfway house...they wouldn't have paid to help her marry him anyway, so that worked out. But I know MIL would have liked to be able to do MORE for us...she just didn't have the money, and so didn't offer any suggestions at all (and suddenly I have a new insight into why she NEVER gave me ideas for anything...maybe she was afraid she would be asked to pay for them?).
So there could be a huge embarrassment factor, if your friend doesn't have a big wedding. But, and I'm just going by hubby's family and all of his Korean or half Korean friends and their families here, I would think that this would all be VERY MUCH discussed already, by the parents to her and to him multiple times. As in, he would know from the parents all that was requested...

This is how it is with her.
And he hasn't told me (or HER, from what I gather), but he HAS told my DH that he would marry her tomorrow if "he didn't have to spend $10,000 to feed 300 members of her family".
I am right there with him.
Glad that wasn't the exact number, b/c yeah, that wouldn't go far to feed 300 people! Especially a multiple course, lots of food just for show, Asian wedding type of feast.
There's one thing that confuses me, here: Yes, in many Asian cultures it is NECESSARY to have a large 500 person wedding. Also, in those same cultures, the brides' parents begin saving for that wedding the second the words, "it's a girl!" come out of the doctor's mouth.

I've never heard of a situation where the parents were insisting on a large cultural wedding but not willing to put up the cash for it.
I'm wondering if it is your friend who wants the big wedding, but her parents aren't so committed to it...
I too wonder if it's truly coming from her parents. Just knowing MIL, she hated it when we just lived together, and was never happier when we were actually *married*...it was a big shameful problem that he was living with someone without being married.