The watchtower is one sick dysfunctional family. There are no such thing as personal boundaries in the watchtower religion.
Perhaps the elders are behind this brother interfering in your family. He is over stepping his boundary and you are letting him. I am not criticizing you for letting this happen because this is watchtower "normal". Until now this was normal to you. It is NOT normal behaviour.
You have the scriptural right to be the head if your house and call the shots. This bozo is trying to be the head of YOUR family.
My advice to you is find a watchtower article about proper headship and scriptures to back it up and tell this guy to buzz off.