1. Purpose of travel - Convocation invite
2. Financial support - bank statements, salary slips, hotel reservations(reserved not booked)
3. Home/Family ties - NOC from deptt. house/property docs (if applicable), leaving children and/or spouse behind (cover letter), flights (reserved not booked)
4. Travel history - if applicable, all stamps in passports to any country
5. Invitation letter from brother
Something to consider while filing...