According to the Laws of War (По законам военного времени) 41 years old

Credits

Name	Character
Raisa Ryazanova She was 37, now 79 years old
Igor Yasulovich He was 40, now 82 years old
Sergei Ivanov He was 29, 46 years old when he died
Boris Smorchkov He was 37, 63 years old when he died
Maya Bulgakova She was 50, 62 years old when she died
Natalya Fateeva He was 47, now 89 years old

Name	Department
Igor Slabnevich as Director. He was 61 (86) years old when He died	Directing
Igor Slabnevich as Writer. He was 61 (86) years old when He died	Writing