Is the appearance of a jinn to my mother at certain times of the year and its disappearance at other times a reality or a hallucination?

The demonic touch is a truth upon which the People of Sunnah have agreed, and the entry of the jinn into the body of the afflicted is confirmed by the consensus of the imams of the People of Sunnah and the Community, as mentioned by Sheikh al-Islam Ibn Taymiyyah. However, not every seizure is caused by demonic possession, as it may have organic causes. In both cases, lawful ruqyah (exorcism) from a righteous reciter who avoids sorcery is beneficial, along with consulting a specialized doctor to identify any organic causes if present.