Prayers not going to help in dead's. Once we live our life and once we want to live it well, that is when we need prayers. Prayers there to communicate with our Father, and we do that in happiness and in sadness, sometime do that without a reason but to thank Him for all the Love He has given to us. When ever we pray, we know that we needs the love of our father, those who pray will have to joy of pray, those who pray for their needs wants relationships, might disappointed with what God offer to them, because it is now how we should pray.
It is make sense to pray when ever you needs to pray... It is what we do with our living God to give us energy to mingle and to live according to the spirit, it is not miracles we should expect, but life.