Why might communist China have decided to help North Korean?

Communist China may have decided to help North Korea to maintain regional stability and prevent a potential collapse of the North Korean regime, which could lead to a humanitarian crisis and an influx of refugees across its border. Additionally, supporting North Korea serves to counterbalance U.S. influence in the region and uphold a strategic ally that shares similar ideological foundations. Furthermore, China's involvement can be seen as a way to assert its role as a major power in East Asia and to safeguard its economic and security interests.