What is the "Al-Wanisah," and what are its rulings and rewards?

Staying overnight at the grave on the first night after burial to comfort the deceased (al-wanisa) is a reprehensible innovation (bid'ah) that has no basis in Islamic law. It is among the misguided practices, and every innovation is misguidance, and every misguidance leads to the Hellfire. The deceased does not need the companionship of the living, as they are occupied with their reckoning and rewarded for their deeds.