What is the legitimate method of ghusl that helps a person afflicted with scrupulosity overcome it, and what is the ruling on running fingers through the hair and rubbing the body during ghusl?

We have warned you that the optimal treatment for intrusive thoughts (waswasa) is to turn away from them and not pay attention to them. The body of one performing ghusl (ritual bath) is like a single organ, and the flow of water over the body does not strip it of its purity. So, however the water reaches your body, the objective is achieved and the ritual impurity (hadath) is lifted. Rubbing the body (tadlik) is a Sunnah, not an obligation. You must run your fingers through your hair until you are reasonably certain that the water has reached the scalp. In ghusl, reasonable certainty is sufficient. We reiterate our warning against intrusive thoughts and indulging in them.