Bailey O'Neill, 12, Dead Weeks After School Bullying

Bailey O'Neill, 12, has died, at a Pennsylvania hospital after being taken off life support. (Courtesy Rob O'Neill via 6ABC)

A 12-year-old boy has died after being placed in a medically induced coma following an alleged bullying incident at his suburban Philadelphia school.

Bailey O'Neill died Sunday, his father confirmed to ABCNews.com. Bailey turned 12 on Saturday. He was taken off life support Sunday morning.

On Jan. 10, Bailey was involved in a fight at Darby Township School in Upper Darby, Pa., west of Philadelphia. The boy was allegedly jumped by two classmates, one of whom hit him in the face several times fracturing his nose, his father Rob O'Neill told ABCNews.com.

"It was an altercation in the schoolyard where kid wanted to fight my son, and my son wanted to walk away," Rob O'Neill said. "One boy pushed Bailey into the kid [who wanted to fight him]. That kid then hit him in the face, then he hit his head on the ground. One pushed him into the kid, then the other kid did the rest of the work."

Bailey was knocked on his head in the incident, his father said, which caused a concussion. From then on, something with the 6th grader wasn't right, his father said.

"He was a perfectly healthy boy before any of this. He was a healthy, funny, goofy boy. There was nothing wrong with him," his dad said.

Courtesy Rob O'Neill via 6ABC

Bailey O'Neill, 12, has died, at a... View Full Size

Courtesy Rob O'Neill via 6ABC

Bailey O'Neill, 12, has died, at a Pennsylvania hospital after being taken off life support.

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O'Neill added that Bailey was sent back to class with an icepack after the incident. He said the two boys were briefly suspended from school after the incident.

Soon Bailey, who was living primarily in the custody of his mother Jina, wasn't the same, his dad said.

"He wasn't feeling good, he was tired and irritable, and then we had him checked in. They found out he had a concussion," he said.

A week and a half later, Bailey began having seizures, his dad said. A friend of his parents told ABCNews.com that Bailey was having refractory status epilepsies, a condition in which the brain is in a state of persistent seizure. O'Neill said they'd happen about every three seconds.

Bailey had to have a blood transfusion after getting pneumonia, the family friend confirmed, and doctors at A.I. duPont Hospital for Children put Bailey in a medically induced coma.

The Delaware County District Attorney's Office says it has opened an active criminal investigation, according to WPVI. Southeast Delco School District officials have said the district is cooperating with the investigation. The school's principal didn't return a call to ABC News.

On Sunday, the following statement was posted on the Facebook page Building Hope for Bailey:

"I would like to thank everyone who has prayed and supported Bailey and his family!! Bailey has been the strongest toughest boy I know. He has fought this battle long and hard. There just wasn't a way to fix this. I wish I could say he will get better but I can't. Bailey has gone to be with God today :( I love you Jina Risoldi with all my heart and I will help you through this. Bailey I love you!!! Please keep Baileys family in your prayers!!!"