Neville WOULD have alerted Jeremy. Because of the unimaginable situation within the farmhouse,he obviously felt powerless to do anything and through the call to Jeremy he would have hoped that he,Jeremy,would have in turn rang the police before it had been too late.
Regardless of the time of night/morning,you wouldn't allow a member of the family,especially your son to sleep through " just because he'd had a long,hard day previously " . Dear me,whatever next ?