He won't invade, Russia could never withstand it. He's negotiating and attempting to look strong on the world stage. Once he gets something to hang his hat on he withdraws and can claim to be a hero at home where I sense he is losing his grip on power, this could keep him in power, that's his strategy.
“he is losing his grip on power”
The average Russian real disposable income is down 9.3% since 2013. 8 years of no gains.