May just want to show him the scripture where Jesus says where there is one or two there I will be also. Then going down that line show him john chapter 3 where he says all those who believe are saved and have eternal life. Show him this from many bibles or the Greek interlinear because it doesn’t say you have to do works like the WT says to be saved. John chapter 6 confirms this because they ask jesus what they have todo and he tells them, not works,. When he brings up James “faith without works is dead” show him Ephesians 2:8-9
Then you can run down the list of people god used. Noah, Abraham, Joseph, and others but except the nation of Israel no organization. Jesus teachings again were against an organization or a temple etc.