No, watching sex - related stories is not a common or appropriate hobby in most social and moral contexts. Such content is often considered inappropriate and may have a negative impact on one's mental and moral development.
No, it's not normal. Watching sexual content often involves inappropriate and unethical behavior. It may also have a negative impact on one's mental health and values.
He should be made aware of the inappropriateness. Maybe have a serious conversation with him about the negative impacts on his mental state and social life.
It's not a good idea. Sexual stories usually involve adult - oriented and often inappropriate content. There are much better and more positive forms of entertainment like reading classic literature, watching educational documentaries or engaging in hobbies.
Black cocks in folklore can also represent courage. In some African folk stories, the black cock is depicted as a brave creature that stands up against larger and more powerful foes. It's a symbol of tenacity within those cultural tales.
One way is to introduce her to various genres of positive literature, like science - fiction or historical novels. For example, '1984' by George Orwell is a great read that can engage her mind in a different way.