He admitted that I knew the bible better than he but that he knew the Watchtower would have the answers to the scripture I was showing him. He was totally closed minded that the Watchtower could be wrong.
Be afraid... be very afraid.
This cult was founded by Charles Taze Russell, in the 1880s. He denied the Trinity and Christ's deity and denounced Christians as having false beliefs and practices. He believed that World War 1 was the Armageddon. He died in 1916.
Jehovah's Witnesses believe that there is one God, who is one person. They allege that "wicked scribes removed God's proper name, Jehovah, from the Bible." They condemn the Trinity, as they believe that Jehovah is only one person; they believe that Jesus Christ was Michael the Archangel before his incarnation as a man; after His death and spiritual resurrection Jesus again became an angel. They believe that the Holy Spirit is not a person nor a member of the Godhead but is Jehovah's active force, which emanates from him to accomplish his will.
JW's believe that after death, we cease to exist but after Jehovah's resurrection, he will recreated him them from his memory. They believe that in the eternal state that there will be different classes of believers with different destinities.
This is a true cult and should your sister become one, she will have very little contact with you or your family, save trying to convert you.
Please avail yourself with a book called "Truth and Error," Alan W. Gomes to help understand JW's as well as other cults that are pseudo Christians. Many claim to be Christians but have no understanding of the faith