Robert you need to go to the Alabama census rolls for 1920 and check all Deloney's looking for Robert as a child. If he was born in AL and still living there he will be listed.
Do you know what part of AL he was from? If not then when you find him keep hunting back his parents on census every time. That will give you time frame for their marriage.If you find family was living in same county you may be able to find their marriage listed. Then contact that county for copy of record. Then check the preciding yrs they werent listed, under Deloneys again hunting for his father. I had to find my family that way. My Deloneys came from western AL. When you find Robert and his father contact me and let me see if I have them in my tree. Right now I dont. Good luck, Sherry