How should you assist a very large man in a restaurant who is clutching his throat and cannot speak?

In this scenario, the man is demonstrating signs of a severe airway obstruction, as indicated by his inability to speak and the fact that he is clutching his throat. In such cases, the Heimlich maneuver, or abdominal thrusts, is the appropriate action to take to clear the obstruction.

Wrapping your arms around his chest while attempting to provide abdominal thrusts would be incorrect since effective abdominal thrusts require upward pressure to expel the object blocking the airway. Proper technique involves placing your arms around the person's waist and delivering thrusts just above the navel to create enough force to dislodge an obstruction.

Encouraging the man to cough forcefully or trying to pat his back may be helpful in minor cases of choking. However, given that he cannot speak, this indicates a serious obstruction requiring immediate action rather than prompting him to cough. Providing oxygen and monitoring would not address the immediate life-threatening situation he is in and would not help resolve the airway obstruction. Thus, initiating the Heimlich maneuver is the most effective first response in this critical situation.