Why does Faraday think his mother (Eloise) can help?

Obviously we haven't seen the whole story yet, so maybe this hasn't been answered & will be answered later. Maybe it won't be answered at all. During the on-island time flashes, when Daniel knocks on the door to The Swan & Desmond comes out, Faraday tells Desmond to look for his mother (whom we now know is Eloise Hawking/Ellie, The Other). He says that she is the only one who can help. Now that we have seen The Variable which seems to have chronicled Daniel & Eloise's life prior to him coming to the island, I am left wondering why he says that Eloise is the only one who can help them. From what we have seen, at that point he didn't know that Eloise was once an Other on the island & that she knew anything about time travel. What prompted him to think that she could help in any way? Did I miss this or has it not been shown yet? If you think it hasn't been shown, then how do you think it will play out that he learns his mother was once an Other?