I'm very sorry that your brother passed away. My sincerest sympathies to you and the rest of the family.
I don't think it's a curse, but I would want to know what he died of, in case it had a genetic factor or anything else for you all to be aware of.
The year progression sounds spooky, but it's no spookier than, say, a time that some people might suffer when Grandma, Grandpa, Mama, niece, and other family members all pass away within a twelve-month period. That's not called a curse. That's called a really sad year.
As far as your brother's saying he was dying is concerned, I've known that to happen. The husband of a friend of my mother's worked for several hours in the garden on a hot day and came in, very overheated; his wife asked him if she could get him a drink of water, and he said, "It's too late," and died right there. That still sends shivers up my spine, but it does happen. When my older son was still in high school, a friend of his was in a very bad accident, and as the EMTs were trying to get him out of his smashed car he said, "I'm going now..." But he didn't. They saved him.