www.familysearch.org is a good place to start. Using your father and his sister's names. If you are uncertain about your grandfather actual name is Cecil best to leave his name out as their parent. If age is unknown please use approximate in a range of plus/minus 5 years and eventually expanding it to 10 years plus/ minus scale. You need to know LOCATION as of last residence or which state, county or city as where Stephen was born. Find the newspaper archive article about the car accident as that will provide some clues. Contact Catholic Charities, a church, or other organization that may assist in finding the Foster parents and what agency they used to obtain your father and aunt as Foster children. Also if your grandfather name was Cecil Scott, then who was his wife.? Maybe obtaining a marriage certificate on Cecil and unknown spouse, then using that may lead you to getting his birth certificate. Generally, prior to the 1960's many community newspapers would edit in their paper "Who and Who was visiting Who or what clubs they were involved in" , also when couples had given birth to a child include father name (spouse first and maiden name) with the son or daughter's birth date. My best guess as to Cecil's birth year would be between 1925 to 1942. Stephen , your father, depending if he recalls how old he was when accident occurred, had to be a minor - under 16. So likely born after 1950 and before 1965.
