People are cremated when they die. Can he be useful in a good land of feng shui?

Useful, because it has been burned, but only ashes, little effect. It can't be used with the one buried before, but why is it still used? After death, why should March 7th and May 7th, especially the first 14 days? Because the soul never leaves, he always surrounds himself with the reincarnated body. When he really proves that he doesn't exist, his soul.