What is the religious ruling on some widespread mourning customs, and is it permissible to eat and drink from the hospitality offered in a house of mourning?

Wearing black for mourning has no basis [in Islamic law] and is permissible for a woman observing iddah (waiting period). Regarding the distribution of juices and biscuits by the family of the deceased, there is a difference of opinion among scholars: some have prohibited it, while others have permitted it. It is not permissible for the hospitality to come from the deceased's inheritance if there are minor heirs among the inheritors. Condolences are legislated for the first three days and are disliked thereafter, unless one of the mourners was absent. As for the fortieth-day commemoration, it is considered an innovation, and gathering to recite the Qur’an for the deceased is not legislated. It is not from the Sunnah to regularly hold lessons and lectures in an organized manner during mourning.