What is the ruling on dealing with a mother's unlawful money derived from renting out a bar that sells alcoholic beverages, and is it permissible to eat her food?

Scholars have differed concerning the ruling on eating from unlawful wealth. Some differentiate between wealth that is unlawful due to its acquisition, which is prohibited only for the one who acquired it, and wealth that is unlawful in itself, which is absolutely prohibited. The preponderant view among the majority of scholars is that it is not permissible to eat food from someone whose entire wealth is unlawful, unlike one whose lawful wealth is mixed with unlawful wealth.

If eating from your mother's food is prohibited, then you should refrain from it gently, while advising her. If you are compelled to eat from it, then estimate the value of what you have eaten and give it in charity, as some of the Salaf did to avoid cutting ties.