Reminds me a little of my brother. When my brother and his wife had their first boy, he taught him (I guess as soon as he could talk) that my Pitbull would "bite his face off" if he had a chance. The poor kid became neurotic with fear that my Pitbull would bite his face off. Throughout his childhood, we couldn't get him to enter the house unless he was assured my dog was contained upstairs.
Your brother doesn't trust your judgment. Interesting.
