Does a wet dream during the daytime in Ramadan necessitate ghusl? And what is the solution for someone who memorizes the Qur’an but is unable to lower his gaze from pornographic scenes, and does he bear great sin for that?

The emission of semen due to a wet dream necessitates performing ghusl (ritual bath) both during and outside of Ramadan, but it does not invalidate the fast, as it occurs without one's choice. It is obligatory to lower one's gaze from what Allah has forbidden. The responsibility is greater for a Hafiz (memorizer) of the Quran, because his memorization of the Quran should lead him to adhere to it and avoid sins, not to violate the sacred limits of Allah. Allah the Almighty has condemned in His Book those to whom He gave His signs, but who then shed them. He described their state in Surah Al-A'raf (verses 175-176), likening them to a dog that constantly pants. This parable applies to everyone to whom Allah has given His signs, but who then sheds them.