Are funeral rites performed for the mentally challenged in the same way they are performed for those who are accountable (mukallaf)?

A Muslim who is insane, if he dies, is washed, shrouded, prayed over, and buried like any other Muslim. It is obligatory to pray over him and supplicate for him. This includes supplication for the elevation of his status, not merely for the forgiveness of sins, just as in the prayer over a child. As for gathering at the deceased's family's home and preparing food, these are forbidden innovations.