Yeah, it makes no sense to transfer a vegetative person to a wedding abroad, unless Corinna thinks its symbolic meaning is so important that Michael should be there no matter what.
But it's clear Michael is not conscious enough to make his own decisions. I'm sure he would have sent a message of any kind to his fans if he was able to do so.
It's a shame that the family feels they have to hide Schumi like he's some sort of freak. If his conditions was made public, he could be a great advocate of people who have suffered similar head injuries, showing that there's nothing embarrassing in his condition.