First I'd like to say how sorry I am this is happening to all of you. Such a nightmare after all the planning and anticipation.
If this was happening to my daughter, I would recommend to go ahead with the wedding on the original date with a small, intimate ceremony at the courthouse/church. They could then push the reception a year forward to their 1st anniversary and have the big celebration they intended. She could even wear her dress if she wanted to.
Life can be full of twists and turns that we must learn to roll with. This inconvenience will turn into a great family story someday. Hang in there.