No obligation, but we can help. According to the law, grandparents are not guardians of children, and it is parents' obligation to raise children. Grandparents bring their grandchildren to help each other. The law does not stipulate that grandparents have the obligation to bring up grandchildren, but raising children is the obligation of parents. For minor grandchildren whose parents have died or whose parents are unable to support them, grandparents who have the ability to support them have the obligation to support them.
legal ground
People's Republic of China (PRC) Civil Code
Article 1074. Grandparents who can afford it have the obligation to support their minor grandchildren whose parents are dead or unable to support them.
Article 27 Parents are guardians of minor children. If the parents of minors are dead or have no guardianship, the following persons with guardianship shall serve as guardians in turn: (1) grandparents; (2) brothers and sisters; (three) other individuals or organizations are willing to act as guardians, but with the consent of the residents' committee, villagers' committee or civil affairs department of the minor's domicile.