The old sponsor will be in trouble for the penalty for over-staying in the country. It is QR 10.00 per day so imagine the amount. If the sponsor will not take the responsibility, he'll definitely go to the detention center and deported back to his home country. However it is the responsibility of your friend that he/she made sure that his RP was being renewed. You can not be that naive not to query the status of your sponsorship, not to wait for 2 years then go back to the old sponsor. Anyway, only immigration can resolve the issue for overstaying, but sure with jail time to be considered. Hopefully your friend can leave the country without spending the night at detention center.