What should be a safe GMAT score for me to get selected for ISB, Hyderabad or any IIM through GMAT?

My brother was a student of the ISB Young Learners Program. He claims that ISB Hyderabad takes a holistic approach while evaluating your candidature. 

Stage 1: Application form, One essay, and Application fee

Stage 2: GMAT / GRE score, Two essays & One Evaluation

Stage 3: Face-to-Face interview

The admission to this program comprises the above mentioned 3 stages designed to evaluate your 

• academic background
• your personal attributes
• leadership qualities

Since your question specifically pertains to the GMAT score I will be elaborating on that part only.

Academic profile: Like any other B School ISB stresses a good academic background to ensure the candidates' ability to cope with the rigor of the program. It focuses the most on 12-class and Graduation scores.

As far as the GMAT score is concerned, the GMAT score range for ISB is 580-780. ISB considers only the highest valid GMAT score. It looks at the overall score and does not have any sectional cut-offs. The entrance test be it CAT, GMAT, or GRE are all just one of the many parameters to evaluate students. A candidate with a high score cannot with certainty get admission and similarly a candidate with a below-average score cannot certainly be eliminated. However, if you have below-average past academic records you can compensate for the same through these entrance tests.