Help identifying rank from photo

[Pobeda45]

Also interesting, is that the man to his right is wearing a gymnasterka from what seems to be constructed from U.S. made ( Lend-Lease) HBT.

Too cool, I never knew that! :cheers

Here's another photo and a closeup of the plain shoulder boards.

As a sad side note, grandpa was from a large family--4 brothers and two sisters. Two of his brothers perished in the war. A younger brother, born 1909, was MIA in the fall of '41. The archive says his last letter was sent in September of 1941 and that he became officially missing in 1943. I wonder what happened to him--death in battle? Or equally likely, an even worse fate as a POW? Tragic.

Thanks again for the info!
George