@YULIA-2016DO NOT send passports in post from outside the country. There is a very good chance they will be stuck. immediately send them that email asking for instructions.
NEWS from my end - parents passports got stamped and returned as of today. Date is not one year from stamping but 2 months short of it i.e for 10 months validity. Almost complete, next steps parents will have to travel but that might not happen until sometime next year March or April, so the next set of steps of getting PR card will be then.