I will share about a boy got the biggest growth spurt. How did he grow so much?

In 2015, when I was in 10th grade, I was very popular among my juniors. There was one boy who was in 9th grade and he used to be with me to take my 10th grade books. I was 5'7 that time and he was only 157 cm (5'2) so much shorter than me. He used to sometimes mess with me so I also used to say him 'I am taller than you, even many girls are taller than you.' Then in 2016, when I was in 11th grade, I was 5'7 1/2 and he was in 10th grade and grew a bit and became 5'4. I was then saying him 'you will never grow tall like me.'(please don't get offended with this post because I was only 15 that time so I was still very young). Then he said 'I promise you by the end of this year I will be as tall as you and later even become taller than you.' And in starting of 2017,after my 12th grade just started I was around 5'8 and he was literally about the same height as me. He was tallest of his 3 friends who were taller than him before. he said 'now saw I am same height as you.' And he grew taller than me because at starting of 2020 he came to my home and he was taller than me. He said he was 180 cm (5'11) and I am 5'8 or 5'8 1/2. So he said now I am taller than you hahahaha. I was shocked how he grew from 5'2 to 5'11. I never expected him to grow more than 5'5.