A very quick search at this site, https://www.ancestry.com/search/?name=_Gritskevich&gender=m&name_x=_1, brought up a number of entries with the first possible surname you offered. I actually started with this very useful tool: https://stevemorse.org/index.html.
Though I didn't see an Ivan/John or similar name, there was a name similar to Vasiliy. May I suggest you try the Steve Morse page and see if that brings up any results for you?
I am replying to the group so others will not duplicate this information.