Allow editors to send a messages to all users.

yz-allow-editors-to-send-notices.php

<?php


// Allow editors to send a message to all users.
function yzc_allow_editors_to_send_notices( $retval ) {

    // Get Current User Data.
    $user = get_userdata( bp_displayed_user_id() );

    // Get Roles.
    $roles = (array) $user->roles;

    if ( bp_is_messages_component() && in_array( 'author', $roles ) ) {
        return true;
    }

    return $retval;

}

add_filter( 'bp_current_user_can', 'yzc_allow_editors_to_send_notices' );