How do you reach your loved one who is in the Jehovah's Witnesses?
Pray, pray everyday for their salvation. Pray that the Lord will open their eyes. Pray that God will open their hearts to receive the Gospel and Jesus Christ. You can reason with them from scriptures. But you must first pray. They are taught well to despute the facts. So you must research yourself and be fully prepared. They will probably still deny Christ. But at least you told them and now the Holy Spirit can do His job and convict them. That means He will start to speak to them and challenge what they believe. God bless you! Do not give up hope! It took 12 years for me to accept Jesus. It can happen to you or your loved one.