helping someone decide to stay in the church

Pray for that answer and ask for your church elders or someone of your trusted member there what to do. Don't even tell to everyone what was happening, do it secretly. Then when you gathered all enough ideas you should now set decision before you go to your friend. This is relationship or fellowship normal problem.

Church is both a place for worship and a social environment. The worship function is, or should be, the spiritual element that helps to support a person's faith while the social function is human and so subject to all the failings and weaknesses of humanity. New Christians often expect the more long-standing members of a church to be 'better Christians'. Regrettably, this is often not the case and sometimes causes surprise and consternation. Really, one should see every church member (including the vicar, pastor or priest) as human and, very often, they are a member of the church BECAUSE they are sinners (as we all are) and certainly are no less subject to human weakness than others. Many people come to religion and join a church because they feel themselves damaged or wounded or weak in some way and are seeking support and healing. That is one of the main functions of a church or, indeed, any worshipping community.