What is the best way to handle the situation of a longtime peer suddenly becoming a NCO and supervisor in charge of soldiers/friends?

In the Marines, when I was a LCPL, life was pretty easy. Get to work on time and do as your told. At the end of the day, PRIVATE's, PFC's and LCPL's could entertain one another as the chose. Once I made CPL and became an NCO life with those I hung out with changed dramatically.I don't know how it is now but back in the 80's or maybe it was just within my particular unit, but there was definitely a separation. Enlisted, NCO's and Staff NCO's all stayed within there groups.Don't get me wrong, my friends were still my friends and occasionally we hung out, but I was treated differently, but still in a good way. My subordinates would be couscous when doing something with a mischievous intent. Or when one tried to skate out of thier responsibility. There was a time when a GySgt. tried to write me up when a subordinate was a little disrespectful. I waived it off and my Gunney said if I didn't write him up, the Gunney would write me up. Though the choice was ultimately mine to make, my Gunney was trying to teach me that, sometimes those under your command will get complacent and test your metal as you grow into your new position of authority. I have learned there are thseveral who command respect and those who demand respect. Be the one who commands respect and your men will follow you when you need them the most. And they will respect your command.

I dealt with this as a young NCO. I was a 20 year old E5 and found myself squad leader to my friends. Most of them showed me the respect that the new rank brought, others were jealous of my promotion and one didn't care about listening at all. I explained that I had to hold myself to a higher standard and the "smoking and joking" had to stop. Ultimately I was moved to another platoon. Not because it was hard to manage my leadership and friendships but I thought it to be better on everyone, which it was. Maybe seeing your former battle buddy, now Sgt leading other soldiers places them in a new perspective, and separates them from the situation. So my advice would be a transfer, but maybe not a transfer that takes you out of you unit. It takes years to build good working relationships, its somewhat counter intuitive to undermine the readiness and integrity of the unit to get rid of good soldiers based solely on the fact they were promoted.

From my Experience... One of the best ways to "handle it " treat him with the respect of a nco when in front of peers and subordinates alike just like you would anyother nco what you guys do after work as friends is not important and as far as everyone else is concerned never happened but make sure that is where you leave it .. outside of work