My first thought is RT himself. The Reason is "FEAR" Fear of losing something..
Possibly Barbara was connected to her brother by Soul.
"A spiritual connection between two people that transcends physical boundaries."
RT would be in fear that he would lose Barbara in a divorce and he would lose assets.
His life would be cut in half at 72 years of age.. People can do terrible things for selfish reasons ..
Simple as that ..
The second thought is FEAR again .. This time because BT possesses knowledge of something.
That something is connected to others in their life. Once Barbara is out of the box she was held in, "Not even allowed to own a cell phone or computer, and with RT 24-7" then that knowledge could become public and used as a weapon. They know her brother was very street smart. An intelligent individual who was well connected.
So RT or others move to take away the threat of being exposed..
jmho