Would appreciate input on the following scenario:

Defense attorney is hired to represent Defendant for a felony DWI case. Atty also makes the bond for Def. Def fails to appear and is out and about for a year or so. State files bond forfeiture. Also seeks and gets indictment for bail jumping. Atty withdraws from representation.

Def is arrested and receives court appointed counsel. As of now, refusing to plead to the bail jumping. Prior attorney is willing to testify but is worried that a statement to the effect of, "I told him to be there." would cause issues with divulging confidential client information.

Anyone had this come up? How did you handle it?