Indian Air Force (IAF) Group Captain Varun Singh wrote a letter to the principal of his school in Haryana in September to thank his “teachers, instructors and peers over the years” who helped him shape his life and give a message to the children at his alma mater. Varun Singh, the only survivor of the IAF chopper crash that resulted in the death of Chief of Defence Staff General Bipin Rawat, his wife and 11 others in Tamil Nadu, is battling for his life at Command Hospital in Bengaluru