Is the father's money, which comes from selling food and tobacco products, unlawful?

Earning profit from selling permissible food items is lawful (halal), while earning profit from selling tobacco is unlawful (haram). Your father mixed his lawful money with unlawful money. He should be advised to fear Allah and not mix the good with the bad. It is not permissible to obey him in selling unlawful items, nor is it permissible to eat from what is known to be from the very essence of unlawful money. However, eating from his general wealth is permissible if the lawful portion is dominant.