The thing is, while they call themselves The Firm, the are, at the heart of it, still a family. I think they've closed ranks for now and will not budge or do anything that might make Andrew look like he is guilty in their eyes.
When/if he is proven guilty we shall see what they do and say. It's one of the reasons the family needs to get this out of the way once and for all - this won't go away until they do.
I am looking forward to the walk to and from church this Christmas, to see who interacts with Andrew.