I stand corrected. Avast Internet Security does have a sandbox like browser protection like Sandboxie. But unless his father was running his browser under Avast's Sandbox it cannot protect him.
http://www.avast.com/en-us/internet-security"Surf and socialize without worry
Sandbox lets you surf the web and run even risky programs virtually, outside your PC. And our Web, IM, and P2P shields ensure your safety on social networks (e.g. Facebook or Twitter) and online dating sites, IM chats (e.g. Skype or ICQ), or peer-to-peer file-sharing sites."
There are two different sandboxes in Avast IS. once which analyzes programs and the other to fully virtualize your browser. But this FBI Ransomeware isn't something you download and install. It comes when a user clicks on a malicious link. Then when you reboot your toast.