Blackford's son became ill probably with malaria, the date and details of the sickness are unknown. Blackford took him to Lexington, Kentucky for medical treatment, but he died only a short time later. The death was an emotional blow to Blackford. He returned to Vincennes where he arrived in the night and entered the home of his friend John Coburn. He lay on the floor and wept till morning. He then locked himself away for two weeks in a room in Coburn's home, never speaking and only coming out to receive a meal. As he recovered, he sold his Vincennes estate and invested the money in land.