Combine brown sugar, garlic powder, 2 tablespoons black pepper, red pepper flakes, 2 tablespoons salt, and paprika in a bowl. Rub the spice mixture over pork butt, cover, and refrigerate 5 hours or overnight.
Pour beef stock and 1/2 cup hot sauce in a pressure cooker. Stir in 3 tablespoons honey, 1 tablespoon molasses, maple syrup, and 4 crushed garlic cloves. Place the pork butt in the pressure cooker, seal the lid, and bring up to low pressure over high heat. Reduce the heat to low, maintaining low pressure, and cook for 2 hours.
While the pork is cooking, make the coleslaw. Mix mayonnaise, Dijon mustard, 1 teaspoon hot sauce, white vinegar, 1 teaspoon salt, and 1 teaspoon black pepper in a bowl. Add the coleslaw mix and toss to coat. Cover and refrigerate.
Turn off the heat and let the pressure reduce naturally; remove the lid and let the pork rest for 5 minutes. The meat should shred easily with a fork; if it doesn’t fall off the bone, reseal the lid, turn on the heat, return the pressure cooker to low pressure, and cook for another 30 minutes.
Remove meat from the pressure cooker, reserving 1/4 cup cooking liquid. Shred the meat using two forks and set aside.
Heat vegetable oil in a saucepan over medium heat. Stir in 5 cloves of garlic; cook and stir until the garlic is fragrant and just starting to turn brown, about 3 minutes. Remove from heat and stir in ketchup, 1/2 cup honey, 2 tablespoons hot sauce, 2 tablespoons molasses, cider vinegar, and reserved cooking liquid. Season with salt and black pepper to taste. Bring the sauce to a simmer over medium heat.
Fill each Kaiser roll with two big forkfuls of pork, two tablespoons of barbeque sauce, and 2 spoonfuls of coleslaw.