Secondly, Dr. Jolly West visited Ruby in prison after he was convicted for killing Oswald. Ruby was never the same afterwards.
He was never the same before Wests visit. He had already smashed his head off his cell wall before West showed up.
If "they" wanted to shut Ruby up, it makes no sense to wait until after he was arrested, detained, tried and convicted. Much like it makes no sense to shut Oswald up on the Sunday when hes been in police custody for 2 days. Could've already told them everything about a plot.
And then who shuts up West....
West also worked with Patty Hearst. He did good work there.