It's obvious that the China Russia rapprochement is due to their mutual interest in defending against Western aggression.
What's important, however, is to understand why the West is a threat to Russia.
Before Putin, Russia was run by oligarchs who were siphoning Russian wealth and resources to the West. It's no surprise that this was the warmest period between Russia and the West, and that relations quickly cooled when Putin started putting an end to all of that.
As an aside, there is a remarkable correlation between corruption and Western friendliness. For both China and Russia, the periods of best relations with the West coincide with the greatest amount of corruption in civil service.
So yes, if Putin dies and the oligarchs return to power, Russia may very well turn back West. However, so long as Russia maintains an independent policy, the West will always be a far greater threat to it than China.