The best regulation on that model is achieved via how much charcoal you light. If it runs too hot, the front door that gives access to the coals can be opened, and the temp will fall quickly.
Has your friend modified it? Take a look at this link, and then check if your friend did any of this:http://brinkmansmokermods.com/default.aspx
I've done those mods (well not the goofy feet extensions) I light off 32 charcoals, put them in the pan, toward the edge. Then I fill the rest of the pan with coal, and overlap the unlit coals over the lit coals some. That gives me 240 at my dome thermometer for 3 hrs. After 2 1/2 hrs you want to shake the ashes off the coals, and bank them to one side, then add some more unlit coals.
If your friend has not done the mods, I can't advise you. I did the mods before I ever cooked on mine, and never ran it unmodified.
BTW, chicken is okay to run hotter. You may want to start with 50% more lit coal to run hotter. If your friend does not have a decent thermometer, then shoot for the built in thermometer to point straight up (12:00) That should be hot enough to crunch up your skin. For Pork and beef, you would shoot for the "I" in the word "Ideal" on the thermometer.