I'll try taking a stab at the second one. Let's assume the mother is alive. There's nothing to say that she hasn't given her child up for lost. She also might not want anything around to remind her of her captivity. Considering you used the word 'rescued', it doesn't sound like she had too fun a time. She could have very easily settled down, married and started a family, giving your character full human siblings.
If it turns out the mother did want the baby, well divination is a tricky thing and evey very reliable spellcasters botch. The if the mother was devout she could have gotten a message from Iomedea of 'i need you (location) doing (project)' which could entangle the mother for several years rendering her unable to search.