What is the mother's rights on violating her civil rights?

You need to talk to a criminal defense attorney.

The police will justify the stop with a trumped up traffic violation even if they did not write a ticket for it and that makes the stop legal. If your son consented to the search then the search was legal and they could search the entire vehicle. The issue of whether they could read texts on the cell phones is not one that is litigated often and that would have to be researched. Your lawyer will probably run a suppression and contest the search of the vehicle and cell phone. You and your son should understand your constitutional rights and no one should ever consent to a search even if they think the car is "clean" since it is a violation of your right to be free from unreasonable searches, a valuable right you have that he just gave away. You as the parent should get a lawyer to instruct him not to talk to the police, answer their questions, consent to a search, or fall for their lies, threats, or false promises. You should have the cell numbers of three criminal lawyers in your wallet just as you have your medical insurance in your wallet in case you have to go to the hospital. You prepare for such emergencies so that you and your family know what to do and say in case of police contact or medical emergency.

If the stop was truly illegal, then what was found could not be used against the driver of the car. It might be used against third parties. If the police misread the meaning of the message, and then the mother were charged, a good criminal lawyer should be able to get the case dismissed before trial. Good Luck.

Mothers do not have rights. If the search was illegal then get you a good criminal lawyer or traffic court lawyer who knows the law of search and seizure

Get a criminal lawyer. I do not understand what gave the cops the right to check the cell phone.

I think that you want to get a civil rights attorney to sue the police for the results of the illegal search.

None, because the son consented.