China and Russia are not natural allies. China is not sending Russia weapons at least not that many. However China benefits a lot from this. It is able to buy oil and gas the US navy can not cut from Russia, is able to move its influence into Central Asia, the area of the world with the weakest natural Western influence and the West is looking at Ukraine rather then Taiwan.
It is going to hurt Russia long term, but it also might make it a complete puppet of China.