Is the action of my 14-year-old brother, who claims that prayer is not yet obligatory for him and that he will commit to it once he reaches puberty, correct, and should I compel him to pray?

A child is commanded to pray upon reaching seven years of age, and is gently disciplined for it if they reach ten years and refuse. This is based on the Prophet Muhammad's (peace be upon him) saying: "Command your children to pray when they are seven years old, and discipline them for it when they are ten." Some jurists are of the opinion that prayer becomes obligatory for one who reaches the age of ten. Therefore, if your brother is approaching puberty or has reached it, his guardian must command him to pray and discipline him for abandoning it, so that he may become accustomed to it before reaching puberty.