I just confirmed.  One-level only:

function myCallbackFunction(user) {
	console.info("user: " + user.name); /* works */
	console.info("manager sysid: " + user.manager); /* works */
	console.info("manager name: " + user.manager.name); /* does NOT work */
}
function getInfo() {
	var user = g_form.getReference('requested_for', myCallbackFunction);
}