Silver sees various flashbacks of Lilia learning how to care for a human infant, such as going to Baul for advice and singing him the same lullaby as Maleanor would sing to Malleus.
It seems that Malleus, too, remembers the tune of the lullaby (though possibly not the words), but Malleus does not seem to remember where he learned it from. He guesses it was from a nursemaid so it is possible that Lilia sang it to Silver but not Malleus, or Malleus has forgotten.
Via flashback Silver learns how Malleus was not particularly enthusiastic about Lilia adopting him, telling Lilia that just discovering the infant didn’t mean that he had to raise “the thing” and saying Lilia could have dropped him off in a human land.
Lilia quotes Malleus’ father, saying that he hopes to learn more about humans through Silver and whether or not he is even capable of loving a human. Malleus asks, “What if you aren’t?,” and Lilia responds, “I’ve got plenty of time to find out.”
It seems Malleus was also present when Silver first stood on two feet.
In a Chat Malleus tells Silver that Lilia once told him, “Raising children is a nightmare even with magic”. Silver responds, “O-oh…he really said that?!”
Silver also sees himself saying his first word: calling Lilia “papa,” which he learned from a book that Lilia read to him. At first Lilia tries to explain that he is not truly Silver’s father, but then decides that they can save that discussion for when he is older.
Twisted Wonderland Reference Note 