Is it permissible for the mosque to set up a mourning tent and rent it to the family of the deceased to generate income for the mosque and reduce costs for the family of the deceased?

It is permissible to rent out a portion of the mosque for a permissible matter that is compatible with its status, in order to spend on it, provided that this portion is not needed for prayer and that the majority of the mosque's congregants agree. As for holding condolence gatherings in a house or a tent, it is disliked (makrooh) and contrary to the Sunnah. Therefore, it is not permissible to set up a tent for condolences inside the mosque or its courtyard.