I would definitely have an attorney! Even if he is pleading guilty he needs someone to speak on his behalf. Good luck!
You ALWAYS need a lawyer when charged with a criminal offense. Before agreeing to an "interview" and certainly before "confessing".
I am assuming he is a juvenile? If he is and this is first offence he will likely get community service, probation and may have to make restitution.
As long as it isn't a large amount and it is a first offense it shouldn't be too bad.
If you have a right to representation, take advantage of it!
I am not familiar with the laws of Canada, Lonewolf would probably know!