I suspect it was because eyelashes get sun and fade, there was no mascara in those days. I did a web search and couldn't find anything so this is just a guess.
Start with his birth certificate, do you know the date, town and county he was born in. Those are public records and a copy can be obtained from the county clerk for a fee.
I did a web search of the mane and came up with several; Richard a graphics artist, Juan who does comic art of a sort, and Jean a interesting old painter. I would suggest a digital photo and see if Sotheby's can help you. You might be on to something. Good luck.