Write a letter to your brother inviting him to come and stay with you in the hostel for a few days.
My Dear Sujal,
I was delighted to receive your last letter. It is good that school has closed for its summer vacations. You must be finding it difficult to pass the time.
I think that, if you come and spend a few days with me in my hostel, you will enjoy yourself. In the morning, you can spend some time in reading story books or your text books of the next class. In the afternoon, when I return from my classes, we will have lunch together. After resting in the afternoon, you can play volley ball with my friends and me.
Give my love and respects to respected Papaji and Maaji. Please ask them to give you permission to come here for a week.
Yours affectionately,
XYZ.