WHY DID THEY OPT TO LOOSE SUCH A "MODEL" FAMILY? COULD'NT THEY COMPROMISE AND TRY TO CONVINCE THEM TO STAY ( INCLUDING THE "BROTHER/FATHER")?
If the father was being DFd for apostacy and then was able to convince his entire family, pioneers and MSs among them to leave with him, I'm sure that the elder body would be afraid that he would lead others into apostacy. They have to cull the herd of the troublemakers.
It's not about compromise, it's not about model families. It's about control.
DFing the entire family in one fell swoop isn't the end of the elder's troubles either. JWs being the gossipy bunch they are, people will be talking about this for some time. This elder may have already planted the seeds of doubt and discontent amongst others in the congregation. This could lead to quite a few people starting to doubt, then question, then leave. Whether they DA or just fade away, I'd be willing to bet there'll be some fallout.