Repenting for committing zina with one's sister
Q: One of my friends whom I know for years told me an upsetting story.
His story was that he had committed fornication with his sister when he was 12 or 13 years old. Now that he is 20 years old, and knows what he has done, he is worrying every second and regretting his life. He says that his conscious does not let him live and he has no hope to be forgiven by Allah. What is your kind directions to him?