Final answer:
Ferrous sulfate should be administered with orange juice as it enhances iron absorption due to its vitamin C content, which helps convert ferric iron into the absorbable ferrous state.
Step-by-step explanation:
The nurse should reinforce to the parent that they should administer the medication ferrous sulfate with orange juice to enhance the medication absorption. The absorption of iron mainly occurs in the duodenum and the proximal jejunum, where acidic pH favors the absorption of iron by converting it from ferric to ferrous state which is more readily absorbed. Orange juice is an excellent source of vitamin C, which plays a crucial role in converting ferric iron into the more absorbable ferrous iron and enhances iron absorption from the gastrointestinal tract.