This is another red envelope for my eldest brother. How should I reply?

You can reply "Don't think too much, I pray for good luck". In our daily life, language is our way of communication. Whether typing or speaking, we need our language expression ability, and different words can express different meanings. Therefore, I suggest that you read more books and study more at ordinary times, so that you can better express your meaning and purpose in communication and let the listeners accept it better.