My son is driving me crazy. He's a tRumper.

I was thinking we were beginning to have some halfway civilized conversations and then he blew up over something today and I just want to write him off, but that means I write off the grand kids too.

My sister has older kids that are having issues. One daughter "S" is a off and on meth addict. So when "S" is clean, my sister lets "S" see her own daughter who my sister is the guardian for due to "S" is not a healthy parent.

My sister had the "audacity" (my son's words) to hurt his kids feelings. She bought tickets to a water park so that my son's 3 kids could attend a B-Day party with the daughter of "S". The water park is like 5 cities away from my sister's house, but she drove everyone out there (because it was really close to my DIL's parents house where they are house sitting) and called my DIL to say they were picking up the cupcakes and would like to meet at the water park.

Everything was fine until my DIL found out that "S" would be there at her daughter's birthday party. She often leaves these events early but her daughter was having so much fun "S" stayed a bit longer.

My son is blowing up about it (because it cut down the time his kids could be there by 4 hours) and doesn't want anything to do with that side of the family any more because he wants to support my DIL's sobriety - "S" got DIL the meth and DIL fought the issue for 3 years and is finally keeping it together.

Now if he said this calmly, it would be one thing, but he is screaming at me and my sister for wrecking his children's lives.

I told him he is over reacting and he says, "No" I have am tired of bending over and not being heard about this."

As I see it my sister bent over backwards to accommodate them and it was a free water park invite that he chose to pass by for reasons that we can support.

In fact, my sister said she will make a special trip to pick up the grand kids on another day to take them without the involvement of "S".

My son rejects this as any kind of solution.

He is so unreasonable. One thing he said is that if "S" shows up at his house, she will get a shotgun in her face and my son doesn't care if he goes to prison for it. He will "probably" give her the chance to just leave, but not certain about that. He is off the wall on this issue and many others.

What do people do in this kind of situation?

I can't just ignore it, normally my son and his family live with me (rent free - but he blames me because they had a chance at section 8 but I wouldn't sign saying they paid rent for a year because they haven't and I refuse to lie in that manner and wind up in prison for welfare fraud.)