When Harvey was admitted, he claimed both of his parents had died. However, House was suspicious as Harvey claimed both of his parents were accountants, but Harvey lived in a very run-down neighborhood. House believed accountants would have been better at ensuring their child was taken care of.
When Harvey became unconscious and they couldn't get informed consent, House turned to Cuddy who told him that House would have to prove Harvey had no next of kin before he could have a guardian ad litem appointed. Instead, House ordered his team to look for Harvey's parents. Cameron was phoning someone and when she mentioned Harvey's name, they hung up. House realized they had the right people and called back to say someone had to come in to identify Harvey's body.
When Mr. and Mrs. Park arrived they were furious at the deception. However, House argued that given Harvey's condition, they were just a little early. They refused to have anything to do with their son. They had found out that he was a masochist and had disowned him. However, House threatened to reveal to their entire community that they had let their son die, feeling that would have more impact on their honor than the perversions. Mr. and Mrs. Park agreed to the surgery, then left the hospital.
After Harvey recovered, one of the thing he asked was whether his parents had come to see him.