What do I do when my boss sucks the life out of my team?

I’m wondering if you can give me some advice on managing my boss. I am really into trying to build on the positive with employees and I spend a lot of time in our staff meetings trying to give credit where it’s deserved and cast management decisions in a positive light. However, my boss tends to follow up my comments by saying something that sucks all the positivity out of the room. He is a really good guy and I don’t think he realizes the does it, but he speaks badly of former and current employees to me with the office door open so the people who sit nearby can hear. He also acts like employees can’t be trusted. We recently participated in a top 100 Companies to Work For survey, and people came to me and asked if I wanted us to win or if I wanted them to be honest. Of course I want honesty, but it concerns me that they would ask. Also, I recently conducted a peer review wherein employees were asked to finish the following statements about each of their peers: please do more of this, please keep doing this, and please do less of this. The response for my boss was overwhelmingly to stop making negative comments and treating employees as if they are expendable. I’m nervous to bring this up with him, because I don’t think he even realizes he does it, but I feel like there is a consistent pattern wherein he negates praise or recognition with a small but cutting comment.

I am really hoping that this community of leaders and coaches can help me move forward to be able to give my boss the feedback he needs to hear, in a way that will make me feel confident to do it, safe… and with the best potential for results. Thank you in advance for your guidance – I would like to learn more about a “coach-Approach” but more than anything I want my boss to realize the impact he is having and want HIM to use more of a coach-approach to HIS leadership.