add_filter(
   'friends_friend_feed_viewable',
    function(
        bool $false,
        $pagename_parts
    ) {
        // Your code here.
        return $false;
    },
    10,
    2
);

apply_filters( 'friends_friend_feed_viewable', false, isset( $pagename_parts[0] ) ? $pagename_parts[0] : false )