Combine the water, brown sugar, kosher salt and pink salt in a large container. Stir until the sugar and salts are dissolved; let the mixture cool. Place the ribs in the brine and place a weight like a plate on top of the ribs to keep them submerged in the brine. Cover and refrigerate 4 to 5 days.
Remove the ribs from the brine and place in a smoker at 225 degrees F until almost tender, 5 to 6 hours. Refrigerate the ribs until cooled. Once cooled, cut between the bones to make single ribs.
For the sorghum mustard glaze:
Combine the sorghum, Dijon, mustard seeds, fish sauce and pepper in a saucepan and simmer, uncovered, for 20 minutes.
Heat the oil to 350 degrees F in a deep fryer. Submerge the ribs in the oil and let them fry until crispy and hot, 4 to 5 minutes. In a large bowl, toss the ribs with the sorghum mustard glaze and transfer them to a platter. Garnish with green onions.