What was the first thing Malala's father did that made his own father smile?

The first thing Malala's father did that made his own father smile was win first prize at a public speaking competition.
In the book, Ziauddin tells Malala that he found it difficult to please Rohul, his father, during his childhood years. For his part, Rohul was an impeccable scholar and eloquent orator. In fact, he was known for his speeches. Rohul taught theology at a high school and the village of Shahpur. He was also a local imam, whose sermons were invariably attended by enthusiastic locals from the mountains.
In contrast, Ziauddin struggled with a persistent stutter, which greatly embarrassed him. To make matters worse, Rohul was a terribly impatient man. When Ziauddin stuttered or grappled with his enunciation, Rohul merely roared at him. Of course, this did not help at all.
Despite this challenge, Ziauddin tells Malala that he was determined to win his father's esteem. When he was thirteen, he announced that he was entering a public speaking competition. For his part, Rohul was skeptical that his son could make him proud. However, Ziauddin persisted: he asked Rohul to write his speech and promised to learn it.
At his speech, Ziauddin performed so admirably that he won first prize. This was the first time that he had managed to make his father smile. As time progressed, Ziauddin went on to participate in more public speaking competitions. Rohul wrote his speeches, and he delivered them with aplomb, almost always coming out first. This prompted Rohul to call his son a shaheen or falcon.

Malala's father Ziauddin has a fraught relationship with his own father, Rohul. This is a complete contrast to the relationship that Malala enjoys with Ziauddin, which is loving and supportive. Malala's grandfather has a clear, compelling speaking voice, one that he uses to good effect in delivering sermons and lectures and in reciting poetry. Ziauddin, however, has a terrible stammer. Nevertheless, he's determined to earn his father's respect, so he signs up for a public speaking competition. Not surprisingly, Rohul is more than a tad skeptical, but he agrees to write a speech for his son to deliver. Ziauddin practices the speech for weeks, and on the day of the public speaking competition delivers it perfectly. His speech is such a huge success that he wins first prize. Not only that but he finally earns the respect of Rohul. Ziauddin tells Malala that this is the first time he's ever done something that has made his father smile.

Malala and her father have a loving relationship, but her father, Ziauddin, and his father have much more of a strained relationship. When Ziauddin recited a speech written by his father at a public speaking competition and won first place, overcoming his stammer, it was the first time he had made his father, a respected orator, smile.