Is it permissible to wash and pray over a deceased person whose body has decomposed?

Washing the deceased, praying over them, and shrouding them is a communal obligation (fard kifayah) by consensus. This obligation is not waived if the corpse is decomposing. Rather, the deceased should be washed as much as possible, even if by simply pouring water over them. If washing is not possible, then tayammum should be performed, and the deceased should be shrouded, prayed over, and then buried.