How sound is the claim that dreams are inherited from fathers to sons via chromosomes? And can a person see a dream that one of his ancestors saw? And how sound is the hadith: "The truest of your dreams are those of the truest of you in speech"? If it is sound, then what is its meaning? And how was the dream of the King of Egypt, which Joseph, peace be upon him, interpreted, found to be true, and was he a righteous king?

We do not know of anything in Islamic law that supports the validity of the first part of the question. As for the hadith (definition): "When the End of Time approaches, the dreams of a Muslim will rarely be false, and the most truthful in dreams will be the most truthful in speech," it is authentic. Its meaning is that a Muslim's dream is the most truthful among people's dreams, but this does not preclude the truthfulness of a non-Muslim's dream as well.