All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad (saw) is His Slave and Messenger. You bear no sin for giving your email address to your father, and such an act is not Kufr (disbelief) in any way. Moreover, you are not sinful for the fact that your brother accepted the license agreement without reading the terms first and without holding the intention of approving only whatever of those terms conforms with the Sharee'ah and rejecting those of them that contradicts it.
Allaah Knows best. (Source: islam_web) Classified in Fiqh of Transactions and Inheritance > Contemporary Financial Issues