NS 2015

Getting ready to install NS in about 3 weeks (already worried about this) 5 license. One of the license I will install on my Brothers next door. He does not use the vault or Identity safe. Do I have to install this on His PC ? The reason why I ask is this, He is getting very forgot full in His golden age and some times clicks on things what He shouldn't. Then I have to go and clean the PC up. What worries me is this,  my Norton account is connected to His and maybe gets compromised. Is there a way He can have His own account and email address instead of mine?  If this is not possible I guess I need to buy just 1 license for His PC .

Thanks in advance.

NanaH