Hello. My name is Lena. After reading your post message, I decided to reply.
I don't know if this will help you or not, but my last name is Kuchmy. We are from Ukraine. Another spelling of this last name is Kuchmiy. I have a lot of relatives living is Washington, USA with this last name. (I'm in Washington too). I heard from my father that he had two uncles who disappeared during WWII and to this day they do not know where they are.
Anyways, let me know what you find out about your gradfather.