Which she was if she had to admit the truth. Every single moment she spent in her childhood home felt like a dream she didn't understand. If they'd actually been there for a visit the Christmas before she ran off, that must have meant that the confusion she had about her parents happened after that holiday. Neither her mum nor her dad treated her any differently than they had in the past she could remember. The secret of her diminished mind must have remained a secret from them. Or Antonin would've made a more believable lie about her being in a longterm care ward inaccessible by Muggles, not a South American rainforest researching magic. Her past as a shit mum and wife wasn't a surprise to her parents apparently if they weren't even horrified by her absence for so long.