Suzanne and Todd Connell say their young son Bobby has been bothered by nightmares since witnessing the Feb. 24 death of SeaWorld trainer Dawn Brancheau, the Orlando (Fla.) Sentinel reported.
The couple sued SeaWorld for negligence and damages from emotional trauma, but Friday Orange County Circuit Court Judge Julie O'Kane dismissed a count of negligent infliction of emotional distress.
She reserved judgment on a second count in the suit, intentional infliction of emotional distress.
SeaWorld's vice president of communications said the company is "gratified" with the ruling.
"We look forward to her decision on the remaining count," said Fred Jacobs. "We are hopeful that the court shares our view that the Connells' suit is without legal merit. The safety of guests and employees and the welfare of animals have been and remain our highest priorities."
Brancheau was pulled underwater and drowned by the 6-ton killer whale Tilikum. The Connells said their son was 30 feet from Brancheau when she was pulled underwater.