technically quite easily possible.........however more likely he has used exagerated figures from the manufacturer....
in my room i have
fronts 150watts x 2 = 300 watts
hifi fronts 100 watts x 2 = 200 watts
centre 100 watts x 1 = 100 watts
sides 100 watts x 2 = 200 watts
m/c/a sides 100 watts x 2 = 200 watts
rears 100watts x 2 = 200 watts
sub 500 watts x 1 = 500 watts
so i have 1,700 watts of speaker power handling rating......wooohoo...heh
however, when it comes to actual power output to drive them, driving them all my AV amp probably only manages to output a total of 400watts and my stereo amp 500watts total, oh plus sub of 500watts (guesing its able to do close to that? cant remember what consumption is on it now, say take of 100 watts to play safe) so 400 watts on sub, so thats 1,300 actual output capability.....
doesnt mean a lot tho if it sounds poo....lol.....he might just have a couple of big PA type club speakers which can go rather loud but lack quality.....my system can manage pretty good volumes (havnt tested properly but i did just my stereo speakers, no sub, and managed almost 90db and i reckon i could have gone louder...just not willing to risk it...lol).....and still sound fantastic