I'm so sorry to hear about your son's friend. Suicide is so horrendous, as is the depression that sometimes triggers it. I love the points you make about this, and the beautiful flower photos. I've been seriously depressed - years ago, thankfully - and one thing I've learned is that every state of depression is different. That's why it's so difficult to help someone who's really depressed. They can't see that it's a temporary state of mind.
When I was doing my Mountain Leader Assessment, one of the Assessors had been a member of his local Mountain Rescue Team, and he had a lovely dog who had also been part of the team. He told me about an occasion when his dog had been sent out to find a woman who had left her home in a suicidal state of mind. It took the dog less than an hour to find the woman, and her life was saved.
A few weeks later, this man received a letter from the woman, thanking him and his dog for saving her life. She said that her partner had been ill for years and she had been worn out caring for him. When he eventually died, she just went to pieces, all the exhaustion hitting her at once, and she suddenly couldn't see any reason to live. After being rescued, she came into a more rational frame of mind and realised that she had a lot to live for. I think Buddhists say that it's just a negative state of mind passing through.