He'll have a great time, we were one of the first countries to have legalised gay marriage, we fought, won against water charges,
for a small country, it's come a long way, travel wise, check out Galway, it's both chilled out AND there's great nightlife, good hostels.
The Arran Islands, never actually been myself, that really DOES have thatched cottages, would be quite (I'm guessing?!) traditional.
Belfast also worth checking out, they don't take euro, but it's a good city, though weirdly, soon as the shops shut up, the city empties?
Dublin is a good city, a LOT to see and do.
Waterford, Wexford, Wicklow, the Wicklow mountains, all brilliant IMO.
There's great raves on, like 24/48hrs, or however long they go on before they get shut down by the police, usually around Blessington (Wicklow).
And way more places.
He'll have a great time.