The US seems to see Venezuela as Russia and China's outpost in the Americas. Given the refocus on Monroe Doctrine, it makes sense they would view it that way. Instead, it would be a great outcome for China if this became America's next Afghanistan/Iraq.
Won't happen for a number of reasons.
That he hasn't utilized all that oil money to buy significant military hardware from China, it's a testament to his idiocy and incompetency. America attacking Venezuela now, while not justified, for sure follows the law of the jungle.
There is no such thing as oil money. Venezuelan oil industry is basically non-existant beyond what Chevron had been extracting and most of that money goes to pay debts, including Russian and Chinese debts. The fact that is Chevron shows Trump is full of shit, too.
The rest is dilapidated and non-productive which is why can't even break 900k BPD on its own.
Why wouldn't Russia and China not help venezuela, like they said in the US "Its a nice deal, we give ukrainians money they kill Russians" like Mearsheimer like to say "What's good for the goose is good for the gander"
At this point I seriously doubt Russia and China will do anything more that strongly worded letters, maybe some excedent Gerans and spare parts for the S300V and Buks.