An attorney can represent co-defendants, but it is not typically recommended as one defendant can be called to testify against another and thus cause a conflict. It sounds as though your current attorney is aware of the conflict which would result in him not being able to represent either defendant unless both you and the co-defendant waive the conflict. You may want to consult with another attorney if you are not satisfied with your current representation and if there is a conflict, then a new attorney may bring that issue up with the Court.
Answered on Jan 14th, 2019 at 8:50 AM