First of all it is to be stated that matters of punishment in the grave or what happens after death including heaven and hell are all beyond ken of human cognition, and, therefore, we must not speculate about them based on our limited human reason; to use reason to judge or evaluate such matters is no different than using a scale meant for measuring gold to weigh a mountain. However, a Muslim’s belief should be that people would be accountable and they will be rewarded or tormented as much as they deserve regardless of the state of their bodies in this world.
Sheikh Muhammad Al-Hanooti, member of the North American Fiqh Council, states: If anyone passes away in a crash, burned up into ashes or drowned in the sea and was eaten by sea animals, nothing of that will change the status of what we call “the torment of the grave”. We don’t know any physical or substantial details of that status of the grave. The only thing we know is that people would be accountable, and they will be tormented as much as they deserve because of their sins, or they will feel good and happy as they know their position of the Jannah or Paradise.”
Sheikh M. S. Al-Munajjid, a prominent Saudi Muslim lecturer and author, adds:
“The torment or blessing will happen to the body as well as the soul in the grave, and also in the Hereafter, in either Paradise or Hell.
With regard to those who die by drowning or burning, or are eaten by wild animals, their souls will have their share of torment or blessing, and that will come to their bodies on land or in the sea, or in the bellies of the wild animals, as much as Allah wills. But most of the blessing or torment will come to their souls which remain, either in a state of blessing or a state of torment. The soul of the believer will go to Paradise; the Prophet (peace and blessings be upon him) said: “The soul of the believer is a bird which hangs from the trees of Paradise, eating their fruits; the soul of the kafir (disbeliever) goes to Hell.”
Every Muslim man and woman has to accept what Allah and His Messenger (peace and blessings be upon him) have told us, and believe it as it was meant by Allah, even though some of the meaning may be hidden from us. And Allah has perfect wisdom, may He be glorified.