The engines are factory forged and can support a lot of power. DO IT!!!
While that is true, the transmission will melt and you need to do plenty of upgrades besides the supercharger to make it worth it. If he really wants, he should be able to get $10k for his car. Then he could buy a 96-98 with a built engine and supercharger for $10k, there have been a ton of great cars for that price lately. They have good driveability, make 500whp and everything has usually been rebuilt so they will hold up better than supercharging that 06 V6.