Hello,

The number of attempts(years) for JEE Main is three. And these are like this, first one is when you are about to pass the class 12th or just passed. And two more attempts in the next  two succeding  years.

Now for JEE Advanced, you get one less attempt than JEE Main. So, the total number of attempts(years) for JEE Advanced is two. One in the passing year of JEE Advanced and the other one is in succeding year.

Now coming back to your question, see if your brother is giving improvement exam in 2022 and his original 12th exam is in 2021 then he will get 3 chances for JEE Main in the year 2021, 2022 and 2023, but if he is freshly giving 12th exam in 2022 I mean not giving improvement then he will get three chances and these are in 2022, 2023 and 2024.

You can think the same for JEE Advanced but you will get one less year of attempt.

To know more about JEE Main in detail you can go through the link below.

https://engineering.careers360.com/articles/jee-main-number-of-attempts#:~:text=Students%20can%20appear%20in%20the,passing%20their%20class%2012%20exam.&text=NTA%20has%20not%20mandated%20any,appearing%20for%20the%20JEE%20Main.

To know the same about JEE Advanced, you can go through the link below.

https://engineering.careers360.com/articles/jee-advanced-eligibility-criteria

I hope this information helps you.

All the very best!!