I have no experience with this but searched the cic website. Source and quote found below. I suspect, given the time frame and description you provided, he will not be deemed inadmissible, but that is only my opinion. Hopefully others can tell you more. As for whether or not it delays processing, I would be interested to hear what other members have to say to that as well.
SOURCE
http://www.cic.gc.ca/english/visit/conviction.asp#deemedDepending on the nature of the offence, the time elapsed and your behaviour since it was committed or since you were sentenced, you may no longer be considered inadmissible to Canada. You may be permitted to come to Canada if
you are able to satisfy an immigration officer that you meet the legal requirement to be deemed rehabilitated; or
you have applied for rehabilitation and your application has been approved; or
you have obtained a pardon; or
you have obtained a temporary resident permit.
Deemed rehabilitation
You may be deemed rehabilitated if you meet the requirements of the Immigration and Refugee Protection Act. Depending on the nature of your offence,
at least five years and as many as 10 years must
have passed since you completed the sentence imposed for your crime. Deemed rehabilitation also depends on whether you have committed one or more offences.
In all cases, you may only be deemed rehabilitated if the offence committed would be punishable in Canada by a maximum term of imprisonment of less than 10 years.You are not required to submit an application to be deemed rehabilitated. However, before arriving at a port of entry, we strongly advise you to contact a Canadian embassy, high commission or consulate outside Canada to see if you qualify.