Love so dearly
Ivy's words were still reeling in Noah's mind. She was genuinely grateful to him for coming into her sister's life while in fact, it was him who was thankful. It was Aria who had crashed into his life and not the other way round and he was happy that he got to meet such a lovely woman.
Other than being thankful, he was also remorseful. But he had no choice. It was either he chose to disclose the secret about her father who was in his comatose condition and see her heartbroken, or wait until he recovered and then tell her about him. At least that way, his woman would not be dejected though he might end up sabotaging his relationship with her in both the scenarios.
In any case, his choice would always be the second option. He could not make Aria sad at any cost and Ian had promised him that he would develop the medicine for his father-in-law. So, the only option he had was to wait for Ian and to not give up hope.