Might Sinn Fein take their seats so as to support their old comrade Jeremy Corbyn?

The standard wording of general election forecasts is that the figure for MPs required to form a majority government 'exclude Sinn Fein MPs, who do not take their seats'. 

However, if Jeremy Corbyn is a few seats short of a coalition majority then might Sinn Fein take their seats in order to support their old comrade, and if so what would the quid pro quo be?