Bike ticket ?

Well, he can do one of 3 things. He can

1. Pay the ticket,
2. He can fight it in court which still requires he pay for it and if he wins he'll get a refund BUT if he loses he'll have to pay additional money in court costs, or
3. He can ignore it and have a warrant put out for his arrest. When he gets picked up he'll rot in jail until his hearing or until he pays the ticket.

Police don't give out tickets just for fun. He broke the law somehow even if he doesn't want to admit it. The reason for the ticket is printed on his copy.

They don't just give you a ticket for riding on the road.

I am sure that he didn't get a ticket "all of a sudden". What was the infraction? Unless he can prove that he didn't do what is indicated on the ticket, he has to pay the fine.

Nobody gets a ticket "all of a sudden". He had to be doing something wrong & the cop observed it. Pay the fine. As pointed out - "The reason for the ticket is printed on his copy." Open your eyes & LOOK.

What was he doing to get the ticket, they don't just fall from the sky? The ticket should specify the alleged offence; if he wasn't doing whatever is alleged then he should contest the ticket. Otherwise he should pay up and learn from the experience.

As most states cover bicycles as motor vehicles as far as the law is concerned he (you) obviously committed some infraction of the same and thus , you got ticketed . A non driving friend of mine was ticketed for drunk driving and had to attend the local drunk driving class and go to AA meetings as well as pay a fine for riding his bike while intoxicated . At the time he didn't even remember that it was me who wrote the ticket and took him to jail , thats how drunk he was .
Laws are written for a reason , usually to protect the public and , that includes Auto and Bicycle users . Just because you are on a pedal cycle does not mean you are exempt from traffic regulations . And remember , while on a pedal cycle you are required to use all proper hand signals and to stay as far to the right as safely possible .
Being a law enforcement officer as well as an avid cyclist and coach for a local racing club , I make certain to teach safe cycling to all my charges .

He needs to go to court. Not going is NOT an option. You should,discuss it with your parents.

Soccerref

go to court or pay it or get arrested then go to court

The only way he won't have to pay the fine is if he can convince the judge that what he was doing didn't violate vehicle code. Bikes are treated as vehicles and are subject to all the rules that car drivers have to follow. The most common tickets that bicyclists get is for running red lights or stop signs, and riding against traffic.

All of a sudden ? I think not.
I'd believe unobservant since
that's the usual ticket curse.