If all Pomfrey was good for was dishing out potions, then Julian would rather rely on himself. He didn't know this woman; she could be making it worse, for all he knew. At least he personally knew the potions he took - every effect, every ingredient, every possible outcome that the potion could cause. But Pomfrey could lie to him about the potions.
Nevermind that any potion he got that he didn't make himself could also have hidden ingredients that he didn't know about.
But, oh... Potions, though it didn't require as much magic as the other subjects, did need some. What... how could he make potions? He would never be able to become a potions master, would never be able to create a health potion. Julian couldn't trust others to make it for him. They'd steal his idea and take all the credit.
At her request, he sat back down. Perhaps... perhaps he could speak to Pomfrey, if only to see how far along his magic was to disappearing.
"The same thing I have been doing," Julian replied, feeling more than a little dazed. "I make up excuses and lie through my teeth. You know, typical Slytherin behavior."