Britt Reid, 22, pleaded guilty to a string of pending charges — including carrying a firearm without a license, a felony — as his trial was to start, prosecutors said.

They will seek six to 14 months of jail time, while the defense will seek probation. A sentencing date has not been set.

Britt Reid brandished a handgun at another motorist in suburban Philadelphia on Jan. 30, the same day his brother was arrested for a drug-related traffic crash, police said.

Defense lawyer William Winning said afterward his client admitted what he did and was remorseful.

Besides the firearms charge, Reid also pleaded guilty to simple assault, possession of an instrument of crime and drug possession. Misdemeanor charges of making terroristic threats, making a false statement to law enforcement and possessing drug paraphernalia were dropped.

Reid owned the semiautomatic handgun but did not have a license to carry it on the street, Senior Deputy Attorney General Marc Costanzo said.

The other driver may testify at sentencing.

"He was upset, and in fear, when he saw that someone he was in the middle of an argument with produced a weapon," Costanzo said.

Reid has undergone outpatient treatment the past few months at the Malvern Institute, which treats addiction and psychiatric disorders, his lawyers said.

Britt Reid's 24-year-old brother, Garrett, faces a mandatory minimum of three days in jail after pleading guilty last month to drug and traffic offenses.

Garrett Reid admitted to using heroin the day he ran a red light in Plymouth Township and hit another car. He apologized in court and said he was attending a residential rehabilitation program.

"Both boys are doing very well in their rehabilitation efforts," Winning said.

Both sons lived at their parents' home in Villanova at the time of their arrests.