Is inheritance permissible for the father if its source is illicit (drug dealing) with the father's knowledge, and is it permissible for the father to build a mosque or perform Hajj with this money, and is it permissible to give the money to someone to take lessons in the Holy Quran as a continuous charity on behalf of the deceased?

Unlawful money is of two types: The first is that which is inherently unlawful, such as stolen or usurped money. This type is not inherited; rather, it must be returned to its owner if known, otherwise, it should be given in charity with the intention that its reward goes to the owner. The second type is that which is unlawful due to its earning, such as money obtained from selling alcohol or working in usurious banks. The preponderant opinion regarding this type is that it becomes lawful for the one who acquires it through inheritance or gift, because it transferred to them through a lawful means. The heir is permitted to dispose of it as they wish, such as building a mosque or performing Hajj with it. It is permissible to give charity on behalf of the deceased with what benefits others, such as teaching the Qur'an or purchasing copies of the Qur'an, according to the Prophet's (peace be upon him) saying: "When a person dies, all his deeds come to an end except for three: an ongoing charity, beneficial knowledge, or a righteous child who prays for him."