MADEIRA BEACH, Fla. — D.J. Mannello, 9, hops off the school bus, bounces into his dad's insurance office in this seaside town and settles into a chair.

"Hi, honey," says Roxanne, his mother. Seconds later, her face freezes.

"Dan," she tells D.J.'s father, "he's having another seizure."

The boy's bright eyes dull. His head droops. He can't speak. His parents take him into their arms.

His father kisses his forehead: "You all right, bro?"

Dennis James Mannello isn't all right. Since he was 16 months old, he has suffered almost-daily seizures, been in and out of hospitals, back and forth to doctors, on and off medicines and diets.

"Nothing seems to help him for very long," Roxanne said.

Dan and Roxanne blame over-the-counter cold remedies they gave their son on doctors' recommendations starting when he was 8 weeks old, when a case of near-pneumonia turned into chronic, thick-mucus congestion. They persist in that belief even though D.J.'s doctors disagree, saying his problems might be congenital or caused by early injury, not by over-the-counter cold medicines.

Since D.J.'s first seizure, his father has been on a mission to get the government to take children's cough syrup and cold medicines off the shelves. The mission has taken him to FDA hearings and put him on national TV. In January, there was a taste of victory — the FDA warned that over-the-counter cold medicines should not be used in children younger than 2.

"Serious and potentially life-threatening side effects can occur from such use," the agency said in its public health advisory.

To Dan Mannello, 42, it wasn't enough: "There are still medicines on the shelves. There are still hundreds of thousands of dosages in people's medicine cabinets."

The search for D.J.'s treatment has gone through half a dozen doctors and hospitals — most recently to Miami Children's Hospital, where D.J. was examined by Dr. Trevor Resnick, the hospital's chief of neurology and professor of neurology at the University of Miami School of Medicine.

Resnick, while reiterating that D.J.'s seizures were not caused by cold medicines, said preliminary results suggest surgery might help. D.J. is scheduled to have brain surgery at the hospital Thursday.

"We're keeping our fingers crossed," Mannello said.

Through his persistence, Mannello was the only member of the public to testify in October before an FDA advisory panel on the safety of children's cold remedies.

"It's too late for my son," he told the hearing officials. "But I don't want it to happen to anybody else. Please do the right thing and remove these drugs from the shelves immediately."

ABC News interviewed Mannello outside the hearing room, and the interview appeared with anchor Charles Gibson on ABC's "World News Tonight" that evening.

The FDA hearings were based in part on a September report, which documented how the agency had received 54 reports of deaths associated with over-the-counter decongestants and 69 reports of deaths connected to over-the-counter antihistamines from 1969 to 2006 in children, mostly 2 and younger. The Centers for Disease Control and Prevention reported last year that at least 1,500 children younger than 2 have had serious complications from the medicines from 2004 to 2005, including three deaths.

The advisory panel voted to ban over-the-counter cold products for children younger than 6. Panel members said there was no proof the drugs helped children and some evidence they caused damage. The FDA subsequently issued its public health advisory in January, warning the medicines not be given to children under age 2, the group most vulnerable to potential harm, studies show. The FDA is studying the issue for children between 2 and 6.

Linda Suydam, president of the Consumer Healthcare Products Association, argued that most problems stem from accidental ingestion or incorrect dosage.

Dr. Joshua Sharfstein, Baltimore's commissioner of health, disagrees. He co-authored a petition that led to the FDA hearings. He started the petition after four children died in six years in his city.

D.J.'s original diagnosis in 2000 was dysplasia without focal point, his father said. Dysplasia is defined as "abnormal development or growth of tissues, organs, or cells." The "without focus" part means there's nothing concrete on which to operate to correct it. The doctor who made the diagnosis declined to comment.

In the same year as D.J.'s diagnosis, Mannello saw a segment on "60 Minutes" about dozens of lawsuits against manufacturers of cold medicines, including over-the-counter medicines containing the ingredient phenylpropanolamine. Several cold medicine manufacturers voluntarily removed the ingredient after a May 2000 study for the FDA by Yale Medical School suggested it might cause brain hemorrhages.

The lawsuits are ongoing, said Hiram "Ted" Carey, of Robinson & Cole in Boston, who is handling some of them. But none has come to trial, and the size of out-of-court settlements isn't known because of confidentiality agreements.

"The big question in the trials is this," Carey said: "Did the PPA cause the injury? If you can't get an expert to say so, you have a big problem."

Dan Mannello tried to join the lawsuits, but his doctors wouldn't give him a diagnosis on which he could base a lawsuit.

Still, Mannello soldiers on. He's working now with Gene Odom, a Tampa, Fla., product liability lawyer.