Final answer:
The most appropriate instruction for discharge teaching after a tonsillectomy is to call the doctor immediately if dark reddish-brown blood is seen in the vomit.
Step-by-step explanation:
The most appropriate instruction to include in discharge teaching for the parents of a child who had a tonsillectomy would be "Call the doctor immediately if you see dark reddish-brown blood in his vomit." This is important because it could indicate bleeding, which is a potential complication after a tonsillectomy.
Option B, "Get him to drink orange juice or iced tea to help soothe his sore throat," is not recommended because acidic drinks like orange juice or strong tea can irritate the surgery site.
Option C, "Try using an ice collar or ice chips to make him more comfortable," is also not recommended because cold temperatures can cause vasoconstriction and delay the healing process.
Option D, "Encourage him to cough and clear his throat to remove any dried mucus," is also not recommended because coughing and clearing the throat can disrupt the healing process and increase the risk of bleeding.