Hi Algis, According to his death record, Kazimir's father was also named Kazimir, and we don't know his mother's name. We do know the family was from Plunge, and Kazimir was a miller or worked in a mill there. Unfortunately, that's all we know.
Martisauskas appears to be a common Lithuanian name. There were other Martisauskas families in Chicago about the same time as ours, but they are not related as far as we know.
Good luck in your searches, and if you find any connection, I'd be delighted to hear.