Question: If i go to heaven but my mother, my father, my wife, my brother and my friends instead go to hell, how can I be happy missing them in eternity and knowing they are tortured forever? How can heaven be a happy place with the sadness of missing the people I love so much?
Answer: That is undoubtedly one of the hardest matters for us to understand. I think the problem is we don’t even now understand how awful our hearts are, or how much justice demands for our rebelliousness. We think we’re fairly good people, not seeing how deserving of punishment we are, how utterly self-focused we are and in need of a rescue. And we do not see how fairly God has given every person a chance to respond to the truth or how foolishly and ungratefully many of us have rejected the truth (Romans 1:18-26).
I can only assume that in heaven I will be able to see what God sees so clearly and I will see the justice of what he has determined as the consequences of sin. This is not to say that I will have no sadness over those I love not being with me. As Paul says, “I shall know fully even as I have been fully known,” and “now faith, hope, and love abide, these three; but the greatest of these is love” (1 Corinthians 13:12,13). Paul is talking about the coming of the complete, mature or perfect kingdom of God which, when it comes, renders certain spiritual gifts or abilities unnecessary (supernatural knowledge, tongues and prophecy) but not rendering love unnecessary. Love will always abide as the greatest virtue in the kingdom. And if that is the case how could love not feel pain for lost loved ones?
But this will not be crippling pain or pain taken out of context from justice. In Revelation 5 we see the apostle John in heaven examining the scroll sealed with seven seals and no one is found at first who is worthy to open the scroll. We know from the rest of this prophecy (Revelation 6) that the scroll contains the terrifying judgments poured out on the earth in preparation for the coming Christ and his kingdom (sword, famine, pestilence, earthquakes, etc.). But seeing this from heaven’s perspective, John does not rejoice that no one can open the scroll and unleash this judgment. He weeps that no one is found who is worthy to open it. Seeing things from heaven’s perspective, John longs for the outpouring of this terrible suffering, not because his love for people is blunted but because his sense of justice is heightened.
Our sense of love and justice and truth and holiness and wisdom will be heightened in heaven and we will never feel more like God feels than then. He tells us,
Say to them, As I live, declares the Lord GOD, I have no pleasure in the death of the wicked, but that the wicked turn from his way and live; turn back, turn back from your evil ways, for why will you die, O house of Israel? (Ezekiel 33:11)
Adrian Perry recognized the suspect seen in surveillance video broadcast on the local Memphis news channel, WHBQ. It was her 20-year-old son, Derriontay, and he appeared to be trying to rob a couple while armed with a handgun. She didn’t think twice about what she should do. She picked up the the phone, called police, and turned in her own son. He was arrested without incident. “I love him,” she told WHBQ-TV. “This is what you call tough love, something a lot of parents need to start doing.”
Love doesn’t contradict justice. The psalmist asks for God to put away His indignation toward Israel and revive her again, but recognizes that though He speaks peace to them they must not turn back to folly (Psalm 85). When he sees God’s answer he says, “Steadfast love and faithfulness meet; righteousness and peace kiss each other” (verse 10). Heaven will be the perfect union of love and faithfulness, of peace and righteousness, mercy and justice. They will be intimate partners in our souls. We will grieve and rejoice at the same time.
Ask the Pastors 
I have asked this very question.How can I find joy,if when I get Heaven a don’t see my Son,who died from a Drug overdose.I can’t say for sure that he ever asked Jesus into his heart.Or if before he took his last breath,if had time to out the name of Jesus.And my other thought is,that I go the rest of my life crying over my Son’s Salvation.When I became a Christian,I prayed for my children’s souls and God will to be done in their lives.Never once did I ever think that any of my children would die and not be saved! My heart breaks over this.How do I find peace? I don’t know what is happening with me.I find myself feeling different when I hear people praising God.And thinking to myself .yeah until some bad happens,like are you praising then?I still pray,I cry out to God to show me that my Son is in heaven.But there nothing but silence.So believing I’m not going to know until my own death.Instead I ask God to give me peace,but yet again nothing.Can help me understand?
How does God have joy if any of His creation does not end up in heaven? But He does, and so will we. But that doesn’t mean we don’t hurt because our loved ones don’t join us in eternity. We do and we will. It would be awesome if God let you know that your son is in heaven with Him. But He hasn’t. That doesn’t mean your son isn’t in heaven. As you said, perhaps he did receive the Lord at some point. But in the meantime, your peace comes from the knowledge that God loves you and is caring for you, and you can trust Him. He only does what is right.