I think
@Lalli meant that a very different Ceausescu could have maintained the support of the army, while OTL's ruler was unable to do so.
I'm not finding clear results about a USSR-Romania or a North Korean extradition treaty. China currently has an extradition treaty with Romania and France, but not with the USA. However, Ceausescu was no ordinary criminal. It's possible that a UN resolution could sanction any country harboring Ceausescu, and the UN could also set up a tribunal like they did for Slobodan Milosevic.
I think the most likely scenario for Ceausescu, if he had survived, would be trial by either the UN or a multinational tribunal of some sort. Extradition back to Romania could possibly result in a death sentence, but the UN or a European multinational tribunal would not be able to use the death penalty, and so Ceausescu would end up living out his life in prison. (The death penalty was abolished in Romania in 1990; the last executions were those of the Ceausescus.)
There are few examples in history of a massacre of civilian protesters leading to improved stability for the punishing regime. There are lots of examples of times when using force against protesters has actually galvanized support for the opposition, both locally and globally. The Boston Massacre of 1770 and the storming of the Bastille are just two examples. Suppose Ceausescu had been able to order the army to fire on the protesters, and suppose they actually obeyed the order (which is not at all certain). This would be covered by television cameras and reporters of all stripes. The response internationally would have been one of sheer outrage. The UN, NATO and other supranational groups would be involved, and Romania would be either sanctioned or invaded, depending on the Kremlin's position on keeping Ceausescu in power. It being 1989, chances are good that the Soviet Union would distance itself from the Romanian situation. The Ceausescus were executed in December 1989,
after the fall of the Berlin Wall in November of the same year.
Overall, Ceausescu might have stayed in power a little longer if he had scared the crowds away with machine guns. The absolute best, near-ASB scenario for Ceausescu is that his regime collapses shortly after the end of the Soviet Union. The worst case for him is OTL. Somewhere in the middle would be life imprisonment.