Hi Sandy, thanks for your post. Right now I can state confidently that if Jakub Schwarz was born in Ungvar in 1904, his birth record may be found, same as information on rest of family.
If he was living in civil union and had kids in Ungvar, they also may be found.
However, I can help you only with his Ungvar period. Events after his migration to Slovakia and Hungary can’t be traced from here.
Please check your mail, I have specifying questions to you.