I doubt that any aristocratic family, especially new money, would immediatly embrace the idea that their Son had a baby with a Maid without demanding some type of proof. And it would have to be more then Mrs. Hughes seeing the two of them having sex and Ethel being pregnant at the right time after. The family could easily argue that if Ethel was having sex with their son then she was having sex with other people. Ethel could protest all she wants but it is nearly impossible to prove that she was monogamous. This is before DNA testing.
It appears that the family desperatly wants Charlie to be their grandson so that there is a connection to their deceased son. They have an easy out if they wanted to take it. The good news for Charlie is that they wanted him to be their Grandson, so he is. He will grow up with many advantages that he would not have as the son of a prostitute or even house maid. Will that make him happier? Who knows, money does not mean happy. William's Dad seems to be pretty happy as a farmer and the Grantham's seem to be worried and upset a fair amount of the time even with their position and money that is continually given to them from people outside of the direct bloodline.
Edited by ProfCrash, Jan 24, 2013 @ 8:04 AM.