The Russians will do nothing to aid them, probably accusing them of resisting and killing many of their countrymen and in reprisal taking large swaths of land and destroying their culture. I foresee many millions of Ukrainians leaving for Western Europe if that scenario becomes reality, which could destabilize Western European nations.
War isn't about destroying tanks and airplanes but occupying the land of your opponent. Russia certainly has a leg up in that regards since they're sacrificing hundreds of thousands of young men to stop the Ukrainians from advancing and could even take Kiev next year.
If Ukraine loses it will mean yet another huge blow to the West. And all this started because we prodded them to become NATO member. They even put their desire for NATO membership in their Constitution! I believe this was the straw that broke the camel's back and inspired Putin to invade.