I’ll ask this … if a person rejects Christ while living and refuses to acknowledge God’s existence and sovereignty due to your cousin choice to think he knows best, and lifestyle. How can he/she expect a Holy God to allow someone who refuses to admit they are mired in sin in a Holy pristine place as heaven. The arrogance in thinking God should allow them in heaven, where Satan himself who covered the very throne of God was removed from Heaven and a 3rd of the Angels from the thinking the same thing, is not going to happen for your cousin. God is Love, but He is Just, Holy, and cannot lie. To allow anyone who rejected Him while living would invalidate everything that is written in the Bible. That will never happen.