Like there is no sadness or sorrow in heaven, only joy, and if we fail to meet up with our family members there would certainly be sorrow.

A characteristic of Isaiah’s prophecy is that he often describes eternal things with pictures taken from Old Testament daily life. Another example is in chapter 66:18-24 in which events that take place in the New Testament church and in the new heavens and new earth are described in terms of horses and wagons and Sabbath days. Hell is described as worms.

Because of the other passages that state very directly that there is no death in heaven, we understand verse 20 as a reflection of the poetic language of Isaiah. He sometimes describes heavenly things in earthly language.

On the other hand, he sometimes describes earthly judgments with language appropriate to judgment day. See the description of Jesus’ ministry in chapter Isaiah 35:1-7 for another example of mixing of literal and poetic language.

This verse from Isaiah that you cite is about being freed from all of the sorrows of this life. Verse 17 means essentially the same thing as verse 19. It does not address the issue of whether or not we will know people in heaven. In 1 Thessalonians 4 we read about meeting our loved ones at Christ’s return. In some accounts there are recognizable people in heaven such as Abraham in Luke 16. We have no details of what these relationships will be like in heaven, but it appears that we will have relationships with those whom we knew on earth and with those we did not. Whatever caused pain in those relationships here will no longer be present there.