since childhood (they're 4 years apart in age; Liam and Noel are 5 years apart, and that age difference is part of the problem), I'm not surprised they didn't. I honestly believe that if they'd tried, Liam would have blown it all up and made all the news about the latest fight.
It seems like a miracle that they were able to reunite for this tour. But Noel is no longer married to his second wife, who did not get along with Liam and vice versa. And Liam's fiancee has done a lot to rehabilitate him. His 4 kids - one of whom he had nothing to do with for the first decades of her life - are also reportedly mellowing him out. It's probably really good for him to see his two sons getting along.
Liam and Noel are still reportedly keeping their distance from each other offstage, staying miles apart, and Liam has really cut down on his drinking and partying so there's much less chance of him being drunk or hungover...or being unable to resist a snide comment that will start a fight (and yes, I know Noel would snipe at Liam, too; they're envious of each other).
Fingers crossed they'll get through this tour, and possibly continue working together, maybe doing more albums. Their mother would love it if they could bury the hatchet - and not in each other's back. Their partners and kids would love it. Their fans would love it.