Most executive briefs are summaries dressed up as decision documents. They tell leadership what happened and why, then end with a recommendation they already knew was coming. That is a status report, not a brief.
A brief starts with what you need. Not background, not context, not the story of how you got here. What decision is required, from whom, and by when. That goes first. If the executive reads nothing else, they know what they are being asked to do.
Background comes second, but only the background that changes the decision. If removing a sentence does not affect what the reader should decide, remove it. Most briefs are twice as long as they need to be because writers add context to demonstrate they understand the problem. Executives do not need your demonstration. They need the decision.
Options with trade-offs come third. Not all the options, not the exhaustive list. Two or three with the material differences between them clearly stated. If you only have one option, say that directly and say why. Pretending there are choices when there aren't wastes everyone's time.
The brief ends with your recommendation and what happens if no decision is made by the deadline. That last part is important. Inaction is a choice, and its cost should be visible.