If his account is correct he shouldn't have a problem beating the charges provided they can locate a witness or video, and with them he's got a slam dunk civil rights suit against DOHS
If his account is correct he'll have a hard time either beating the charges or winning a civil rights suit. If you leave a vehicle during a traffic stop and refuse an order to get back into the vehicle, your behavior is generally considered threatening enough to give law enforcement requisite cause to detain you for a patdown. In the US, the relevant SCOTUS case is Terry v. Ohio and in Canada they have R. v. Mann. At this point, you are in a legal state midway between freedom and arrest and further noncompliance with demands is resisting arrest. Since his account does not include any necessity of medical treatment, it's unlikely that any excessive force used was of such a degree to make a "slam dunk" case. It's nevertheless disappointing that this event occurred but he obviously was terribly mistaken about the extent of his legal rights once he was stopped and began refusing law enforcement demands. I have no doubt that the same chain of events could easily occur if one was to resist a legitimate patdown in Canada.
Why won't sharks eat lawyers? Professional courtesy.