What is the ruling on someone who molests his sister without penetration, and is there an interpretation for seeing her pregnant by him in a dream?

Allah has forbidden the preliminaries of intercourse with a non-mahram woman, and this prohibition is more severe and a greater sin if the woman is the sister whom Allah has forbidden perpetually. The man must repent from this heinous act and fear Allah. His vision might be an ill omen and a warning to him. He must fear Allah and beware of the disgrace in this world and the ignominy in the Hereafter.