First of all, is your family saying a daily rosary every day and a specific time with no exceptions? This is the first and foremost action that must be done.
Second, find a traditional chapel that is not affiliated with the local diocese.
Get him out of public or private school and homeschool him. He is learning what constitutes "abuse" from these evil people.
If he is already graduated or close to graduation from high school and has reached the age of majority, he may have to be sent packing. As difficult as this will be, you cannot allow him to usurp your authority as parents (that is, unless you are locking kids up in closets for hours or using whips and chains as punishments, in which case, he is probably right--but something tells me that this is not what is going on).
Plus, what Charlemagne said.