Is this sentence grammatically correct At this time you should read this communication again and ensure if you are traveling with your family that everybody is fully briefed?

The sentence is mostly correct but could be improved for clarity and punctuation. It would be clearer if rephrased to: "At this time, you should read this communication again and ensure that, if you are traveling with your family, everybody is fully briefed." Adding commas helps separate the clauses and enhances readability.