What is the ruling on eating from the money of a brother who earns it through unlawful means? Does this affect the acceptance of good deeds for forty days? And can anything be done to atone for a deceased brother who ate from this money?

If one is not certain about the unlawfulness of a specific item brought by his brother, the preponderant opinion is that it is permissible to eat from it. This is because the Prophet, peace and blessings be upon him, used to deal with Jews and eat their food. As for the deceased brother, it cannot be definitively asserted that he consumed unlawful things. It is prescribed to frequently seek forgiveness and invoke mercy for him, and it is good to perform Hajj and Umrah and give charity on his behalf.