As Tom Ogg and I were approaching idwal slabs we noted someone soloing as we got closer we could see that the young girl (age 17) was struggling and attempting to downclimb. The girl was 40m above the ground in running trainers and no helmet. Upon arriving at the base of the climb, it was made clear that her dad, who was at stood at the base watching her climb, was in no rush to give her any assistance saying "this will teach her a lesson, she'll be fine, she has climbed 6a indoors once before". Even with multiple climbers trying to offer there assistance he was turning them all down, seemingly unaware of the consequences of a fall from such a height would have. Bypassing him and speaking directly to the young girl, myself and tom offered help which at this point was accepted, the dad still trying to get us to drop the matter. I then climbed up to the girl, making the girl safe, and lowering her to the ground. The dad and the girl had left the base of the climb just as managed to get to the ground myself.