I am sorry for your loss. Siblings kind of get lost in the shuffle when their brother/sister die especially if they are adult siblings. Please check out the bereavedparentsusa.org/
to see if they have a chapter near you (it's for parents, grandparents and siblings). They are a national organization that was/is very helpful to my family, I was a person who said "I don't do support groups" but because these people were either walking the same road or had been there it helped in ways people who knew me could not. There are also other resources that might help you on the site.