Hey John tell your buddy his night is going to be miserable unless he is using an under quilt or sleeping on a pad inside his Hammock..
Under quilts don't have to be expensive or bulky either. I use one of these and its made with climashield insulation and keeps me warm down into the mid teens. Tell him to get one of these for 90$ Anniversary Jarbidge It works fantastic you do need a small mat for under your feet so your feet don't freeze. Thats what A lot of hammocks users do when using a 3/4 length under quilt. This will keep him nice and toasty. You can get the Footpad to go with this for an extra 10$ from them.
While I haven't used their foot pad i have used a similar one. It just slips inside the foot box of your top quilt or sleeping bag and does a good job of insulating your feet. It's dual purpose as a sit pad for glassing as well.Have you used the foot pad they sell with it. How exactly does that work