Hazel remembered part of their conversation from the day she found out he was Billy. He said that he didn't look for her when he turned eighteen because he didn't have the money to afford a private investigator.
That obviously wasn't true because he had bought a painting from her Etsy store not long after. But he also said that he wanted to make sure he was able to take care of her because he wasn't sure if she was still mute or not.
In the beginning Will wouldn't have known she was able to speak again. Even if he did find her later on, he had done whatever it took to survive and try to support himself until they could be reunited.
He said he wanted to give her a good life so he didn't dare approach her earlier and make her struggle with him. There was probably some truth to that statement.
