Son and daughter don't get on

I am a bit drunk. So if my post is jumbled, please excuse.
Just returned from my grandson's 4th bday party. It was lovely. The whole family were there but as usual, my older son and daughter, started arguing over nothing. Daughter and said son's wife have never got on ....this simmers constantly. Maybe because I've had one too many, I really can't tell you what it was about. But d.i.l. ended up in the lounge , crying. Son was torn between his wife and his sister. I was torn between them all. I am back home now....can't sleep. I am planning to take them all to London for my big bday next month, but I can't be bothered now. I will let them bang their heads together. Fed up