He was future Soviet politician Valerian Kuibyshev 's younger brother .
Kuibyshev was born on 25 December 1893 in Kokshetau , the son of an army officer .
son was future Soviet Kuibyshev Kuibyshev   's younger son .
Kuibyshev was born on 25 December 1893 in Kokshetau , the son of an army officer .