Thank you for all of your replies.

Those who have younger bro/sis, or those who have children can imagine my situation... It's not easy make my brother to be 100% honest with me...

He didn't tell me what kinda illegal files those r... but he said it's not music... so I assumed that it's porn. after all, what can a 20 yo boy can be interested in...

He said he deleted everything already. What worries him and me is that will he be arrested by the police...

BTW, any parents have good method to discipline a young man?

Again, I appreciate all your help~

from,
an ANGRY/WORRY sister