It's tough, but not burned or dry
Feed your guests some sides and keep cooking because it's just not done yet. Grills and briskets vary mightily, and while some people go by a rule of thumb - an hour to an hour and a half per pound - it might be more and it might be less. Just listen to your brisket and keep your trusty thermometer at your side.
I'm really tired of going out there and fussing with it
Aw, but that's the fun part! If you're truly having problems maintaining temperature or are just getting antsy, pull the brisket from the grill after two to three hours and finish it in a 225°F oven. Mopping and temperature taking vigilance still apply.