Call Southwest and ask them to add it for you. Generally, DIY adding of a TT number to your RR account after-the-fact will *not* add the TT number to existing reservations (and consequently you won't get TSA PRE on existing reservations).
While you had stomach flu symptoms, your doctor most likely prescribed a diet that consisted of bland foods and increased liquids. The BRAT diet is a common acronym used to treat an upset stomach and the stomach flu, according to FamilyDoctor.org. BRAT stands for bananas, rice, applesauce and toast.
For a stomach ulcer, the major thing he'll want to NOT eat are spicy foods since they can make stomach ulcers worse. Also, he should eat three small meals and three snacks evenly spaced throughout the day, sit up while eating and for 1 hour afterward, avoid eating within 3 hours before bedtime, cut down on caffeine-containing foods and beverages, citrus and tomato products, and chocolate.