A hard brexit will hit Ireland severely. The UK is the 5th largest economy in the world, the Irish 40th. Therefore there is much less resilience. Additionally Ireland prides itself on a knowledge economy largely founded on the presence of multinationals in the country. Should the threatened tax harmonization occur within the EU their raison d'être
may founder on quicksand. This is a double vulnerability further magnified by the UK being the biggest export market and UK food being 40% of Irish supermarket goods(roughly) and UK ferry ports acting as
entrepôt ports for Irish trade to and from the EU. Varadkar is doing his country no favours by trying to act the bogeymen thwarting British attempts to extricate themselves from the disaster zone of the EU.
The demographics indicate reunification is a likely outcome at some future point, providing it is seen as of economic benefit to the North.
Is a free health service more of a draw than a political ideal, as far as the majority in the north are concerned? (To give but one example)