Feel Sorry to my Friends

Today, got bad news for friends. His google adsense account has been deleted. He is not eligible to show google adsense in his blogs and websites again… I feel sorry to you my friends. For you to know, he already run his adsense campaign almost 2 years. And he never did any violation to google term and conditions. I still don’t know why google did such a things. He already email to google ask why google want to do that. He need a logic reason. But unfortunately google did not reply any single words.
Is it because google to arrogant to answer it?
My friends quick his jobs December last year to focus his internet advertising jobs including google adsense. His large revenue comes from google adsense. No wonder he is so sad right now. No jobs, google already suspend his account forever..:(
Its start with last month, his gross revenue double up almost 40%. His revenue around 1k / month.
He also used adwords to generate traffic to his site.
Sorry to you my friends..