Theressa,As far as I can tell from census records your grandfather, Charles Miller, was the only child of William and Lena Miller.In the 1900 census, the Millers indicated they had been married 18 years. In answer to how many children Lena had given birth to, the answer was 0.
In my opinion, genealogy is more than tracing a bloodline, it is tracing family history and stories.These include step children, adopted children, or just being “raised” by a family.Our only grandchild is adopted.She is now 16 years old. We are her parents, grandparents, aunts, uncles, cousins, etc.Our family history and stories are her family history and stories.
So your grandfather’s family stories and history are through the Miller and Friday families, which are also your heritage.It seems you recognize that with your research.
But in case your want to try to find the story behind the adoption here is information that might prove helpful.At familysearh.org there is a link to the 1942 WW II draft registrations.These were men born between April 28, 1887, and Feb 16, 1897.It is sometimes referred to as “the old men’s draft.”I hope this link comes through.It is the registration of your grandfather, showing he was born in Newark, NJ (which is Essex Co).