What is the ruling on a person using money mixed with a usurious source, and is its use restricted to only essential needs? What is the ruling on feeding guests with it? And what is the ruling on gifts that the person bought for his friends with money mixed between his father's money and his mother's money, which has a usurious source?

It is not forbidden to deal with someone whose wealth is a mixture of lawful and unlawful. Muslims have traded with disbelievers since the time of the Messenger of Allah, peace and blessings be upon him, despite their lack of restraint regarding usury and other prohibitions. Since the mother's wealth is not purely unlawful, it is not forbidden to eat from her wealth, accept her gifts, or benefit from what she has bought with her mixed wealth. This permissibility is absolute and not restricted by need. One should continue to advise her and pray for her guidance.