What is the ruling on a grandmother who spends on and raises her grandchild born of zina?

If the grandmother earns her money from fornication and spends it on her grandson, then her earnings are ill-gotten and she is sinful. She must repent, for the earnings of a prostitute are ill-gotten gain. Scholars have agreed on this, and the Prophet, peace and blessings be upon him, forbade the earnings of a prostitute.

If the grandson has lawful money or is able to earn, then it is not permissible for him to benefit from this ill-gotten money. However, if he finds no other money, he may benefit from it to the extent of his need, and he must abandon it as soon as he is able to earn a good living.

The grandmother must be advised and warned of the consequences of this evil, and efforts must be made to prevent it by all lawful means.