Putins ideas of what threatens Russia are not rooted in reality.

I absolutely agree. It's just that, if Putin has these unrealistic ideas of what threatens Russia (like an independent Ukraine), and Putin has stated that Russia can use nukes if it is threatened, and Putin is the one who gets to make the call about whether Russia is threatened enough to use nukes... then I really don't like that one man, disconnected from reality, can start a nuclear war.

Yes, but he's so decoupled from reality that if he wants to do that any pretext will serve so I don't think this will make a difference at all. Putin will do what he thinks he has to do regardless of the rest of the world. It's well beyond logic by now. Russia will suffer for decades after Putin is gone on account of what is happening today no matter how much worse he makes it.