Depending on your relationship with your son perhaps a quiet discussion about your concerns may be appropriate. Unless they are expecting you to contribute to the wedding costs or expect other financial support (eg. assistance with housing costs) due to the burdens of an expensive wedding it is their life, their decision and their responsibility to deal with the consequences. This guideline applies whether we think our adult children's decisions are good or bad.
What other people/posters/relatives etc did or did not spend on their respective weddings is simply irrelevant.
A famous matador gored by bull!



. I hope it's improved.
None of our three asked for a contribution but we felt that we wanted to help with the costs. Our own wedding probably cost less than £150. As long as your not being asked for money I’d leave it up to them. I love weddings and have the most wonderful memories of my children’s weddings. I wish the same for you. Enjoy