What was the CGPA of my brother who got a full scholarship at Cambridge University in UK?

I don't have access to your brother's specific CGPA.

For full scholarships at Cambridge University, such as the Gates Cambridge Scholarship, successful applicants typically have a GPA of 3.9 or higher. Other scholarships often require at least a UK second-class honours degree or equivalent.

Scholarship decisions also consider leadership, community impact, and fit with the chosen course, not just academics.