I seriously doubt he can't run his internal setup on a moderate sized UPS for an hour or two.
At work I have 3 HP proliant DL380's, a Equallogic SAN (with 16 hard drives in it), 2 48 port switches, and some other minor appliances running off a Tripplite UPS, it's 5U (2U main unit, 3U extended battery), and I get 2.5 or so hours of life out of that, cost was under $2000.
I don't see how he could be sucking up more power providing internet than that. The customer critical equipment like his routers from Cogeco to to his external wan, switches, the asterisk phone server (I am assuming asterisk), and the like should be on a UPS. His web server doesn't need to be, we can live without his glorious website working for a couple hours
Cogeco is coming this aft to install, I had to reschedule my Sunday installation. Can't wait for internet to work properly.