No Trace of Grandpa Jeffries

My mother ha never known, met, and has no pics of her bio father.
All we have is his name (Edward Debo Jeffries) he fathered my mom April ann and my Aunt lura lee
mom was born on July 27/1942 and Auntie in 1945..she is deceased.But mom is still here. Can anyone help me
ive been researching this for 5 yrs and nothing.
Thank you
PS
Grandma name wa Thelma Sydney Heise aka Diane