Let's not forget the thousands of dollars, restrictions and time that the homeowner is going to incur trying to defend himself from the Crown.
Aggravated assault

Not many civies or even soldiers, will be thinking clearly. Adrenaline, fear, flight or fight, unknown assailant, what is their purpose there, what are they armed with, how far are they prepared to go with their attack. All questions you must answer to yourself, in seconds, before acting to ensure you neutralize the threat without opening yourself up to a Crown with skewed priorities.
Although not the case here, if you use a firearm to protect yourself and family, it'll be seized along with any other firearms you own and will stay that way until you have a favourable decision. Probably a couple of years +/- after the incident. If they determine you used excessive force, you'll likely loose everything. Of course once they charge you, you can also likely expect more firearms charges under firearm and ammo storage laws, dangerous usage, etc. They might let you plead it down by surrendering all your guns, PAL and accepting a lifetime firearms ban.
"I wish to speak with my Lawyer before I make any statements."
Best advice. Identify yourself, show ID, then clam up until your lawyer is sitting next to you.
Probably a good time to mention, for a $25 yearly fee, the CCFR provides lawyer services with firearms educated lawyers, for firearms related incidents.
firearmrights.ca
We need some form of Castle Law here.