arrested for FTA on dui pre trial diversion

A friend of mine was arrested in Washington over the weeked on a warrant for failure to appear on a status hearing. He was orignally arrested in 2003 for DUI. He entered into a pre-trial diversion program had to do an alcohol class, pay a fine and have 4 years probation. He did it, all. This weekend he was arrested on the warrant from 2006 for failure to appear at a hearing the he knew nothing about. Yeah I know typical story. He was taken and put in holding for 15 hours before he was booked in, allowed no phone calls till he was booked and then later arraigned on the charge. The judge said "State, where is your case here? Somehow, I don't quite understand they ended up sentencing him to another 90/90 days suspended, 2 more years probation and a 1000 fine with 1000 susp. He had no legal representation, they offered a PD, he declined as he had a lawyer handle this case from the begining, and was unable to contact him. He spent a total of 35 hours in jail on something that never should of happened. Oh and also that he had no valid license. Hello, yes he has a valid CDL that does not expire until June. Is this right? Can they do this?

Not sure of the question--with the failure to appear warrant they can arrest him??