Is what the jurist said about the existence of sorcery from the mother and a close female relative true, and what should be done regarding the proposed treatment, and how can one treat oneself from this sorcery?

The person you went to is not a jurisprudent (faqih); rather, he is a sorcerer. This is indicated by several clues: his specifying a location for the alleged magic, his claiming that its cure is incense and water, his specifying a particular time for bathing, and his informing you that the magic came from a female relative of yours to cause separation among people.

What is incumbent upon you now is to repent from this action, to feel remorse, and to seek forgiveness, for going to such people is among the grave sins.

Most of those who complain of magic are experiencing delusions and satanic whispers. And if it is assumed that someone is indeed afflicted with magic, then the cure is lawful ruqyah.