Dottie,
If it were me, knowing what I do now.........I would do as alffe said talk and talk with him about it. But more so, I would do just what you are doing....I would reach out to people who can help. I would love to try to help you, but the truth is, I have not had significant training in suicide prevention.
That being said, I would call the free hotlines and ask for advice. I have also found some fantastic sites with great information on how to talk with a friend.
A google search will bring up hundreds of sites.

If it were me, I would share my story. The deep, never ending pain that I was left with when my Dad took his life. If this hasn't happened to you, send him to read stories from the survivors. Let him know he is loved and needed, that you will be there. That you can hang onto eachother and ride the tide together. Best wishes Nikki