This depends upon the interest of your brother. There are huge number of options available for a student with PCM with computer. He can go to BSC, BCA or if he wants to persue a professional degree then he can consider engineering as well. Many entrance exams are there to give admission into top engineering colleges or simply he can get himself enrolled into aby private college.

It's not necessary to go to a science stream with a science background, he can look for courses likhe Bcom, Bcom-honors, CS, CA.
The options are plenty.
Hope it helps.
Thank you