You mention a charge of “assault firearms”, which is not really a precise Criminal Code offence. It sounds like the conviction was under s. 267 of the Criminal Code:
Assault with a weapon or causing bodily harm
267 Every person is guilty of an indictable offence and liable to imprisonment for a term of not more than 10 years or is guilty of an offence punishable on summary conviction who, in committing an assault,
(a) carries, uses or threatens to use a weapon or an imitation thereof,
(b) causes bodily harm to the complainant, or
(c) chokes, suffocates or strangles the complainant.
https://laws-lois.justice.gc.ca/eng/acts/C-46/page-57.html#docCont
As you can see, the Crown has the choice of proceeding summarily or by indictment. In your case, given the sentence you describe, it would seem that the Crown proceeded summarily. Nevertheless, it would appear that immigration regards the nature of the offence as “violent”, since there was exposure to a maximum penalty of at least 10 years.
You say he was sentenced to “a year of house arrest and a year of community service”. That is not likely accurate, but I get the idea. The sentence would have been a “conditional sentence”, with conditions including “house arrest” or a curfew, usually covering the nighttime hours. There would not be a “year of community service”, but almost certainly a term that he serve a defined number of hours of community work service - frequently 50 hours or so - to be performed at the direction of a probation officer, usually within the first 6 months of the sentence.
The following 2 paragraphs are found on the CIC website, as archived material, and, in light of scylla's above post, must be taken as no longer reflective of current policies:
Sponsorship bar for violent crime
The bar on sponsorship for violent crime means that a potential sponsor convicted for committing or attempting to commit a violent offence punishable by a maximum term of imprisonment of at least 10 years
against anyone is now barred from sponsoring a member of the family class to come to Canada. This regulatory change is similar to the current prohibition for convictions of a sexual nature.
Someone who has committed such a serious crime, regardless of who it was against, should not benefit from the privilege of sponsorship.
Duration of the sponsorship bar
The sponsorship bar remains in effect until an individual convicted in Canada is either pardoned or acquitted on appeal, or where five years have elapsed since the completion of an imposed sentence. For convictions outside Canada, the sponsorship bar is in effect until an individual is acquitted on appeal, or where five years have elapsed since the completion of an imposed sentence and the sponsor has demonstrated that they are rehabilitated. The regulatory changes do not alter the duration of the bar.
All of this may be found here:
https://www.canada.ca/en/immigration-refugees-citizenship/news/archives/backgrounders-2011/violent-criminals-barred-sponsoring-members-their-family.html
Given that 5 years have passed since completion of sentence, you are probably okay. But, as others have suggested in the other tread you started on this same topic, an immigration attorney can likely give you more exact (but not guaranteed) information about how these things go in practice. That is largely because, immigration law and practice is pretty much wild west territory and the decision-makers answer to no one.
In any event, if scylla says it's not a problem, it's not a problem. Her post reveals that the serious violent offence "against anyone" is no longer considered and it must relate to a family member. I suppose the fact that the current sponsorship application form asks, at Question #14, about a violent offence "against anyone" demonstrates only a failure of CIC to update the form, to delete that language.
