He will ask the Courier to hand over his/her weapons. If the the Courier agrees, he will confiscate all of his/her weapons (excluding holdout weapons). Not giving them to him will result in him attacking the Courier.
When the player first enters he will ask for player's weapons, in which the player can negatively respond to this and say 'From. My. Cold. Dead. Hands', which is a reference to ex-NRA president and film actor Charlton Heston's speeches.