Yes, heaven is a place of total happiness and peace, and we can be confident that our loved ones who have gone before us into heaven are not disturbed or upset over the evil things that happen here on earth.
The Bible doesn't clearly tell us if people in heaven are able to observe what happens on earth–although there are some hints that they do. In the book of Hebrews, for example, the writer recalls the great men and woman of faith who have gone before us and are now in heaven. Then he adds, "Therefore, since we are surrounded by such a great cloud of witnesses ... let us run with perseverance the race marked out for us" (Hebrews 12:1). Like spectators in an arena, he seems to suggest, they are watching and cheering us on as we seek to follow Christ.
Never forget that heaven's main focus is Christ. Even if those in heaven see some of what happens here, they now see it from God's point of view. And they know that some day "the earth will be filled with the knowledge of the glory of the Lord, as the waters cover the sea" (Habakkuk 2:14).
Thank God for the hope we have in Christ–a hope that is based squarely on Jesus Christ and what He did for us through His death and resurrection. Is your hope and trust in Him?