Please help this is a little complicated?

without any first names it's hard i guess you could start looking in the town he was born in and start calling all the Kelley's tell then what the situation is and see if anyone has ever heard of your great grandma the fact that you know means that your Grand daddy knows which means that he probably knows his dads first name maybe he might have some of his mom's stuff and let you look through it maybe there's some old letters in there somewhere good luck hope this helps