Obviously it must have a very high CFM fan in it and run hot being in entertainment center, so it blows all the time. It does look like it's been in use for years without cleaning, but it depend what the manual say about cleaning.
I had an arctic cooling fan
http://www.arctic-cooling.com/vga2.php?idx=63 in my 9600pro and the fan broke in a year. Started making a very bad noise (the bearing went). It was voided warranty because it had dust build up in that heatsink you see.
It's almost impossible to clean it there, the manual said to vacuum on the rear end of the cooler (which I did) and considering that it broke way before that the 6 year period I finally got a new one. I would have had to pay "repair fee" that was the same as the price of the cooler and all shipping charges, luckily I fought back.
This seems like an identical scenario (except for the trying to clean it part :P), but he can't clean the inside. If manual says some cleaning instruction and he didn't follow them, then Sony did the right thing. If the manual says nothing about cleaning the unit, then thay should give him a brand spanking new PS3 for trying to get out of warranty.