ما تفسير تصرف أختي بضم يدي إلى صدرها تكرارًا، وماذا أفعل حيال شعوري بأنها أصبحت جنسية وارتدائها ملابس قصيرة، مع العلم أن والدتي ألزمتني بعدم التدخل في شؤون أخواتي؟

You must enjoin your sister from wearing short clothes in front of you, and explain to her the obligation of covering her body – except for the face, neck, and hands. You must also forbid her from placing her hand on your chest and warn her of Allah's punishment.

If your sister does not adhere to obedience to Allah, and something that causes suspicion becomes apparent from her, then you must avoid being alone with her, by her going to live with one of her parents, or by one of them coming to live with her.