Birth Family name MAXFIELD

I'm looking for the Birthmom, and family of my father. He was born Dec. 13, 1944 at the Beulah Home for Unwed Mothers. Born and named at birth Robert Maxfield. His mother was 20yrs old. Was 4'11" and of german decent but born herself in Saskatchewan. My dad's Birth weight was 5lbs 13oz. Was adopted and named Charles Richard Gray, the adoption was finalized march 25, 1946. I know that the birth mother had 1 brother and 4 sisters.