That is for sure the case in Cuba, and in fact you can disown your parents in Cuba and they still have to help you monetarily on top of the free housing. Unsure about the specifics in China, could ask around

Yeah there is a real issue with transient homelessness particularly undocumented homelessness, but that’s more of an information issue. I’ve seen interviews where a lot of homeless in this situation are people prone to being tricked and trafficked, so it’s a black market issue that needs to be handled.