For 2007 parents to child (Group 1 ) is €496,824 . Brother to brother (Group 2) is €49,682. Child to parent (Group 2) is €49,682.
If your brother gifts to you then once you have taken €49,682 any other Group 2 gifts/inheritances are taxable.
Your brother gifting to you via parent looks like a gift from him to them and them to you. While this may seem like a way to get almost €50K tax free to you could be viewed as "gift splitting" and Revenue may view it for what it is.
There is also the annual €3,000 small gift exemption which can be taken tax free from any individual so your brother and parents could each give you €3,000 without it affecting your threshold from them.