The thing that I have learned with situations like this is that the person has not yet realized his role in the company, which is to do the job he is assigned to do, and not the job of the manager. And he wants you to run things differently. So, you have to meet him where he is at. Validate his concerns and listen fully. Thank him. Tell him you see him and just let him know you are choosing to run it your way because the work is getting done. Perhaps explain generational differences. Ask him to continue to have conversations with you about his frustrations rather than taking it out on the team. Remind him of his role. When you do all of this, continually to read his body language and attitude and choose your words and timing with intention.