Terrible news. All I can say is that the version of people that we see presented doesn't always represent how they are feeling at the end of the day behind closed doors. I lost a close family memeber of mine to suicide a few years ago. Everyone said the same things "I never thought he would really do it", "he didn't seem that depressed", "last week he seemed fine". Looking back though there were signs but they were not taken seriously enough.
Theres often something else going on in a persons life that is making them seriously depressed. My family member fell into severe depresssion after his son passed away unexpectedly. If you notice a friend or loved one acting depressed talk to them and encourage them to seek help.