Preheat smoker to 225°F and set up for indirect cooking with your preferred wood chips.
Trim brisket point, leaving ¼ inch of fat cap on top.
Apply beef rub generously on all sides of the brisket point, pressing into the meat.
Place brisket point fat side up on smoker and smoke for 4-6 hours until a dark bark forms.
Wrap brisket in butcher paper along with beef stock to keep moist.
Continue smoking for 2-3 hours until meat is fork tender and probes easily.
Remove from smoker and let rest for 30 minutes before unwrapping.
Cut brisket point into 1-inch cubes, discarding any excess fat.
Toss cubes with BBQ sauce and brown sugar in a disposable aluminum pan.
Return pan to smoker or transfer to 225°F oven for 1-2 hours until sauce caramelizes and cubes are sticky and tender.