Megaman, that may not be enough.It depends how the prosecution present the case. The man might be guilty because he was an ' accomplice' present and encouraging the principal offender. It is never necessary to show that a particular defendant inflicted the wound; otherwise you'd never get a group convicted of the offence, and that is a common occurrence in our courts,
That said, the friend needs a solicitor who deals with criminal cases, for the reasons Eddie gives.