This unnamed boy was the brother of Howard.
As a child, this boy drowned in the water (possibly a swimming pool), and despite Howard's desperate pleas to get their parents to realize this, Howard was ignored and his brother died.
Howard resented their parents for their neglect and developed a hatred towards parents who did not put their children first. However, his brother's death made Howard afraid to go near the water, a fear that would haunt him for the rest of his life.
After becoming an employee at Plucky's, Howard had children draw their worst fears onto a piece of paper, which he would then use through fear-based magic to bring to life and punish neglectful parents.
The deaths drew in the attention of Sam and Dean Winchester. After Dean found the subbasement, where Howard conducted his rituals, Howard confronted Dean. Unfortunately for Howard, Dean noticed a drawing by Howard featuring his fear of drowning. Dean used this drawing and a toy made by Howard to conjure Howard's own worst fear: Howard's drowned brother.
Howard fired three gun shots at the apparition, but the wounds quickly healed themselves. Howard's brother approached him and proceeded to drown Howard, thus dispelling Howard's magic. Howard's final words to his brother were an apology, as he also blamed himself for his brother's demise.