We were all newbies at one time, welcome to the fun and games!
To answer your question. If AIB were to be nationalized the share price would fall to zero, as would the ADR. There would be no reason to close the short position as it would effectively close itself.
Many short sellers of stocks, and options for that matter, will close a worthless position for pennies just to free up margin in the account. Eventually that would zero out but to open the margin power the position would need to be closed.