My Buddy is upset with me or Joel I'm not sure

So last night Joel, my buddy and I were sitting out by the fire. And I'm not sure how we got on the subject but for some reason he asked me who would take my kids if something happened to me.

I told him they would go to Joel. It's something him and I talked about a while ago.

Than my buddy asked Joel if I would get his son if something happened to him

No he would go to his mother.

Well that's f#cked up my buddy says.

He was really mad about it. He even left shortly after that.

But why wouldn't he go to his mother. She's still in his life. She is a good mother. She's very involved in his life. We do have him most of the time because he's a nurse and works long shifts. But she's his mom

Why would he think I would get him. I know she would still let me see him. I don't even know why he would care.

I even tried texting him today but he didn't answer.