In most cases, people are at peace because they themselves have nothing to personally fear.
Once I went to a young woman's home about some business to do with the Jack Russell (dog) Club of which she was the secretary. The young woman worked in a bank as an assistant manager. Yet at home she lived in fear. Her father was a drunken violent tyrant. As soon as he learned of my presence, he was insistent on my leaving because he was the owner of the house. He was the boss and he did not give me permission to be enter his premises. The woman later told me that she and her mother and brother lived in fear of their father. He was brutal. Did she have peace when she was away from home or was she fearful? She found some peace by being involved in her work and the Jack Russell (dog) Club.
When we are talking about having peace with God, this is much different. We are talking about being reunited with the Eternal One from Whom we are separated until we are born of His Spirit. Herein lies the difference.
Therefore, since we have been justified by faith, we have peace with God through our Lord Jesus Christ. Through him we have also obtained access by faith into this grace in which we stand, and we rejoice in hope of the glory of God. Not only that, but we rejoice in our sufferings, knowing that suffering produces endurance, and endurance produces character, and character produces hope, and hope does not put us to shame, because God's love has been poured into our hearts through the Holy Spirit who has been given to us.For while we were still weak, at the right time Christ died for the ungodly. For one will scarcely die for a righteous person—though perhaps for a good person one would dare even to die—but God shows his love for us in that while we were still sinners, Christ died for us.Since, therefore, we have now been justified by his blood, much more shall we be saved by him from the wrath of God. For if while we were enemies we were reconciled to God by the death of his Son, much more, now that we are reconciled, shall we be saved by his life. (Romans 5:1-10)Everyone of us is an individual. We have to individually seek God out and express faith towards Him so that we might obtain the peace that is missing in our lives because of sin. Each one who secures his or her own relationship with God, discovers satisfaction that surpasses the mere moments of relief we might mistake as peace on this Earth.
Taking the responsibility for oneself and securing eternal satisfaction might seem selfish to some, but every one of us is accountable for our own decisions and our own actions. We are not accountable for the decisions and actions of other people. If our immediate family members fail to secure their own peace with God, then that is their responsibility and not ours. All we who have secured peace with God can do is demonstrate this in our lives and testify to the goodness of our Heavenly Father, and what is like to know the assurance of being reunited with the Source of Life. To force people to submit to our view or claims is not being peaceful, nor is it being loving. Love permits freewill.
Only somebody who does not know the peace of God and what is like to be reunited with the our Heavenly Father would ask:
"Can a Christian truly be at peace if his or her family member does not have a relationship with Jesus and is thus unsaved?Everything is a matter of personal responsibility and accountability. If somebody rejects God's goodness, then that is that person's prerogative. The Lord God is just. Every decision the Lord God Almighty makes might not make sense to the petty-minded perceptions of humans, who hardly understand themselves, let alone anyone else, but they will be righteous. For those of us who are humble enough to realize that each one of us is only one person among billions of people who are alive on this planet, and our Heavenly Father knows the numbers of the hairs on each one's heads, as well as everything that exists, we leave the decisions up to God when it comes to each one's eternal habitation and make sure that we have secured what is rightfully ours. This is all we can do. What each one does is up to him- or herself. Which is only right, don't you think?
What would Heaven be while knowing that your child or sibling or parent is agonizingly suffering in Hellfire?
Can one truly be at peace, either in this life or in Heaven, while knowing this to be true?
THIS LIFE HAS ITS PROBLEMS AND NOT KNOWING ABOUT THE NEXT LIFE DOESN'T HELP