Such a pity. I would feel miffed in your situation. My DSis had 2 witnesses at her wedding and followed with a garden party for family and old friends and a later party at night for their friends and a few family.
I was a bit sad to not be at the ceremony but it was a similar situation with his divorced DP so they decided to invite no one!
From sinner to saint, quits a transformation.

but surely the obvious solution is just for her husband not to go or for the brides Dad to grow a pair and suck it up.