You need to use the login_redirect
filter returning the redirect location:
add_filter( 'login_redirect', 'redirect_to_home', 10, 3 );
function redirect_to_home( $redirect_to, $request, $user ) {
if( $user->ID == 6 ) {
//If user ID is 6, redirect to home
return get_home_url();
} else {
//If user ID is not 6, leave WordPress handle the redirection as usual
return $redirect_to;
}
}