Well there definately was a civil rights violation here. At no point was he mirandized even though he was hauled away to the police station in shackles and clearly arrested. Further he was detained at the school for more than an hour and a half, and denied his legal request to contact his parents. There were definitely unarguable civil rights violations here.
Whether these violations would net a lot of money in a civil suit is unknown, but I'm guessing they would be unlikely to amount to 8 figures.
Did you read the link I posted above? It addresses your concerns about violations of his civil rights:
Claim: Police should have read Ahmed his rights.
Ahmed complained to reporters that police never read him his rights. He recalled reciting them himself as police were leading him down the hall in handcuffs.
“He should have been Mirandized before the on-campus interrogation — which he obviously was not free to end — even commenced,” Ahmed’s lawyer wrote to City Hall.
But that’s wrong, Peterson said.
“Police don’t Mirandize juveniles,” she said. To prevent any question of intimidation, the law requires children to be read their rights by a judge, in a room with no police officers present. This often happens after questioning.
Even if police had botched the Miranda warning, Peterson said, that would only mean anything Ahmed told them couldn’t be used against him in court. And since the boy wasn’t charged in the end, it’s a moot point.
Bollinger said that questioning Ahmed before he was read his rights was still improper, and “shows a disregard for their own rules.”
Claim: Police should have let Ahmed call his parents.
Ahmed’s lawyers claim authorities broke the law on Sept. 14 by questioning the boy without his parents present — first at school, in a room full of police officers, and again at the police station before his mother and father arrived.
“Ahmed asked nearly immediately if he could contact his parents — which as you know, is his right under the Texas Juvenile Justice Code,” attorney Kelly Hollingsworth wrote to officials. “His request was refused.”
But that’s wrong, Peterson said.
“There there is no right for the child to call their parents,” she said. “The only magic words are ‘I want to talk to my lawyer.’ He didn’t say that.”
The law requires police to promptly notify Ahmed’s parents after taking him into custody. What constitutes “prompt” and “in custody” is often decided in court.
Peterson agreed with Ahmed’s attorney that the boy was likely in custody once his principal led him into a room full of police officers for questioning — rather than about 90 minutes later, when they put handcuffs on him and took him to a police station.
But she said the family would still have a hard time arguing that police unnecessarily delayed notifying Ahmed’s parents.
She cited a well-known court case where police were found to have broke the law by holding a child for days before telling the parents. Ahmed’s roughly 3-hour detention didn’t come close to those to that.