Sudden onset of late stage cancer. They'll lock him away in a hospital. If he gets mouthy they'll state that his medical condition is impairing his mental stability and they'll put him in a psychiatric ward so that he can't say anything until he dies.

It's been done many times before. The practice of using psychiatry as a tool of oppression started in USSR and never stopped. Same people are in charge.

... I guess Putin didn't hear the facts he wanted to hear.