This is because for Calix to have 2 X chromosomes, but still be male, he must have received both an X and a Y chromosome from his father.
This is located in the nucleus of cells and is a thread like structure which contains a vast majority of all the genetic materials.
The scenario mentioned above however, isn't a case of chromosomal rearrangement due to the fact that they were gotten from his father and not from both parties.
Read more about Chromosomes here https://brainly.com/question/3161536