Actually, Locke didn't know anything about Phoenix eggs either but she didn't need to know about that. Besides, who was he to say that the eggs didn't exist? For a treasure hunter, everything exists.
"I'm sure your friends would," Locke said to agree with her as he slouched a little where he sat, getting comfortable. "So don't lose hope! Don't resign yourself to what someone said when you can do something about it. From what I know, the future will always change from what we know. You'll see." He smiled at her.