They sure do bust up families. They bust up relationships before they have a chance to form. They turn people against their families if the family will not come into the cult (how many times has a relative visit been showcased where it got fxxxed up because it was time for the boasting session (it always is) and the relatives didn't want it.) They are always hounding people to bring their children in, no matter what it takes, as well as spouse and relatives.
Then the balloon comes due. One of them sees through the lies or cannot live the strict life that the Tower demands. From there, the person who is "errant" is cut off from everyone else. Children have been put out before 18 for this. Relatives are disowned when they get disfellowshipped or disassociate themselves (why else do they fade slowly). Child abuse, often beatings after boasting sessions where they could not sit still for two or more hours, are common. This puts unnecessary strain on the children. I saw one child that was labeled "bad" because he could not behave himself (i.e., standing still and saying what was supposed to have been said) for 4 or 5 hours of field circus. This, too, ruins families.