Genesis 16:16;17;21 describes Abraham’s first child.
Genesis 17:20 And as for Ishmael, I have heard thee: Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly; twelve princes shall he beget, and I will make him a great nation. 21 But My covenant will I establish with Isaac, which Sarah shall bear unto thee at this *set* time in the nest year.
I have no clue if Joseph’s remains are actually still in this tomb but if they are it sure would be interesting to have a DNA study done to tell us about him.
Joseph, on his death bed, instructed his sons to take his bones out of Egypt when they left and bury him wherever they went. He didn’t want to be buried in Egypt.