Here is Kaisoon at age 22... no swayback from this line
And for temperament, he was a gift from the Egyptian government to the German government, and could therefore not go to a breeder. He was housed, for nearly 25 years, in a zoo, and used, besides for breeding, as a school horse at a children's riding school. While being the most used Arabian stallion in Germany.
So it's safe to say Miss Pity's problems are not coming from his, or the Nazeer line.