What is the ruling on someone who mocks a person who memorizes the Qur’an by saying: "Hajjah"? And what is the ruling on speaking with him?

Mockery and ridicule are not among the ethics of believers. The Shari'ah and the Quran have forbidden them, and only the ignorant mock people. The sin becomes uglier if the mockery is directed at something from the rituals of the religion, as it may lead to disbelief. As for the saying "Ya Hajjah" (Oh, lady/pilgrim), it is not considered mockery of religion, and it might have been a joke. The relative should be advised gently and kindly, and if the person is a stranger, the conversation with them must be according to Shari'ah guidelines to avoid discord.