So sorry, @MummEE2. Also very sorry @PeachesPop.
I'm two and a half years into a similar scenario. My sister died suddenly at 28.
I'm finding it hard to put into words my experiences of trying to support my parents. It's been very varying, and seeing people you love in so much pain is incredibly tough. I would say the usual practical things (try to do as much as possible re the funeral; get in some ready meals if relevant, etc), but also talk about him lots (if it goes down well) - especially as time goes by, keep in touch with his friends for them if you can, tell them frequently how great they are and have always been as parents (assuming this is the case)...
And don't forget that you will need to grieve too, and that even if you think you're "doing alright" things might hit you over time. Sometimes your grief might be too much for you to support anyone else much for a while.
Also remember that everything is a phase. There may be times when you think you've lost your parents or that your relationship with them parents is damaged; you may have thoughts (that might seem childish/selfish to you) that they can't see or truly love "you" any more through their grief, and that your brother's death has stolen not only your brother but also your parents from you; you might feel like you're grieving for your whole family, not just your brother.
But stick with it, day by day, and none of the worst times will last forever.
Sending much love to you and your family. Minute by minute for now.