My thoughts… Your friend may have cooked the pork partly frozen …

Comment on Super Crispy-Skinned Slow-Roasted Pork Shoulder by Ray.

My thoughts…
Your friend may have cooked the pork partly frozen inside.
Also it is important you use a grilling thermometer not length of time.
Often there is a stall in cooking around 150-160 degrees and will need to be wrapped in foil to get over the stall.
Remove roast when it hits 190-195 and rest insulated with towels or in a cooler for 20-30 minutes and should reach 200-210 degrees.

Malcolm Bedell is co-author of the critically acclaimed "Eating in Maine: At Home, On the Town, and On the Road," as well as the junk food blog "Spork & Barrel," and "Brocavore," a blog about food trucks and street food culture. His contributions include Serious Eats, Down East, Eat Rockland, L.A. Weekly, The Guardian, and The Huffington Post and his food truck, "'Wich, Please," was named "Hottest Restaurant in Maine" for 2015 by Eater. Finally, he finds it very silly to be trying to write this in the third person.