Yes, they had to discredit Georges testimony and also explain Caseys incriminating behaviour- all the lies, apparent lack of grief and not reporting Caylee missing. Enter severe abuse. The family acted somewhat odd in the media and seemed to support their daughter and cover up for her, change details in their stories and opinions (though their actual testimonies were pretty straightforward, "chlorophyll" excluded). The defense took advantage of the parents willingness to support their daughter and even lie for her to discredit them. I believe the abuse accusations and just how far the defense was going to go came as a surprise to G/C though, I bet they felt betrayed. And it worked in JB`s favor that George seemed p****d at him (no wonder) on the stand.