Mary Todd Lincoln was the first First Lady of the United States to actually throw a private party at the White House. Before then parties at the White House were open to the public. I can't imagine this happening now, but considering the population of DC in 1850 this was a lot easier. The most interesting of these parties is the wedding reception the Lincolns threw for General Tom Thumb ( Charles C. Stratton) and his wife, Amy Sharpe, who were the very famous two foot tall members of P.T. Barnum's Circus.
The first of these parties was in January 1850. For those who were not invited this was an outrage and for those who were ... they were the talk-of-the-town. This particular party was very stressful for the Lincolns because their 11 year old son, Willie, was sick in bed with a fever. Each of them would excuse themselves from their guests to go upstairs to cater to the boy. Willie died a week later of what we now believe to have been typhoid fever.
Of the President's four sons, only one grew to full adulthood. Robert Todd Lincoln lived to be 86 and served as our 35th Secretary of War. His brother Edward died at the age of four and Thomas at the age of 18. Childhood death was fairly common before the 20th century.