Is it permissible for a Muslim woman to accept money or assets from her non-Muslim mother, who considers what her daughter gives her as a debt, if the daughter's intention is to help and not to lend, and is this considered among the prohibited inheritance between a Muslim and a non-believer?

It is permissible for a Muslim to maintain ties of kinship with a non-Muslim. It is not permissible for a wife to give charity from her husband's money except with his permission, unless it is a small amount that is customary, and both she and he will be rewarded for it. If the mother becomes well-off and gives you something in return for your kindness and generosity, there is no harm in accepting that as a reward, and it is not considered retracting a gift or inheritance, but rather kindness for kindness. It is permissible for a father to reward his child for his kindness if his original intention was to reward him.