This is, per their culture, "ceremonial" formality and behavior, PER the culture and the event it is.
Then, per regular everyday life... there are other, aspects of their culture which impacts behavior. Their "ethos."
BUT... your friend has been in the USA and in college here. And has been around other women and different cultures/lives. AND he is 37, and has had YEARS of unsuccessful dating. So um, why?
But, do not automatically assume, that their "everyday" life will be the same as their ceremonial, duties. Per the wedding.
But even if they do live, this way, ie: the woman being subservient... well isn't that their business?
Its not like that in the USA. But they are a part of another culture, which we as Americans, may deem not acceptable. Or as you say, "disgusting."
The bride, is 18. She doesn't know anything other than her own culture. Being here will be a big shock and culture clash, and a huge difference.
But, if your friend is very traditional... and sticks to the ethos and mores of his culture, then they way they both live, will reflect that.
Even if he lives in an American society, here.
Lots of women, stay at home with the kids while the Husband is out working. Even here in the USA.
But, the "male" mentality and expectations... upon his Wife.. will vary and/or reflect their cultural mores and ethos, and how they themselves were raised.
This occurs in any, couple.
You can opt, not to go to the wedding.
Or, you can talk to your friend about his feelings on it.
But you cannot, change a culture's ceremonial heritage or customs.
And hopefully, no matter what culture or society a Man is from... hopefully, he is not a jerk nor chauvanistic and is nice... to his Wife.
Right?
But this is their culture and life.
A long time ago, even the high society in America, arranged suitors, for their daughters, or sons.
In many countries/cultures, they did this.
Even long ago in Hawaii, many of the immigrants to America, had arranged marriages. It was not disgusting.