Would a Muslim who receive Jesus as his savior privately be saved, as to avoid death and persecution?

I believe so. We are saved by grace through faith. I also know many Christian Muslims that are terrified for their lives and the lives of their family because they have become Christians. Their salvation is not conditional based on how many people they tell, but it may be God's will for them to face suffering, and for their persecution to bring others to the saving knowledge of Jesus Christ. This would be similar to the deaths of the early Christian martyrs. I think your former Muslim friends that now believe in Jesus can be saved privately in their hearts, and they must trust the conviction and discernment of the Holy Spirit when deciding what to share about their faith and who to share it with. I hope this helps. God Bless!