I'm assuming you're in the UK so you may not have experienced the joys and sorrows of an Irish wake.
The wake in Ireland is NOT after the funeral, that is called the funeral reception or some such, but never the wake. An Irish wake is usually at the home of the deceased, the coffin is in the front room for all the neighbours friends and relatives to have a look at the late x or y and say an obligatory prayer over the open coffin, kids and all.
I have in law relatives in the West of Ireland, so I can only speak for them. The wakes are a bit mad, a bit sad, a bit surreal, and a bit "long". The family will wake the deceased overnight and people come and go. There is much sadness if the person is young, or died tragically, but there can be much hilarity if the deceased was older and the death was not unexpected. Due respect and reverence, but a lot of talk, food, drink, sometimes traditional music, and that's all night long. Well for the immediate family anyway.
For the reception nowadays it's a full 4 course sit down in the local hotel/golf club etc. Similar to what a "wake" is in the UK I suppose.
OP, just be yourselves, do justice to your Dad, have lots of photos out and include other family photos. That's usually a conversation opener. Then just celebrate his life. I am sorry for your loss.