If you opt to convince Dean to stay by making it safer for him, you will have to activate two holograms. The terminal to activate the first hologram can be found nearby from Dean's Gala Position, go through the door opposite the one you just came out and down one level/floor. The second hologram is across from the first a little further away from Dean, on the second floor through a hole in the wall. Access to this terminal is through the ruined cafe which is further away (look for the door on your Pip-Boy map). Inside the ruined cafe, take the stairs up. There are 2 doors to Puesta del Sol on the second floor, take the eastern one. From the balcony, walk to the left where there is a break in the balcony walk through in to the hole in the wall, and the terminal is directly in front of you.
(Optional) Turn on both security holograms to guard the courtyard below Dean.
40
Let Dean know it's safe for him to get to his gala position.
Notes
On the second floor inside the ruined store (follow the balcony around across from the second security terminal), is a queen sized bed with a blue cover that can be slept in, regenerating health. If one sleeps there when playing in Hardcore mode it will activate the sleep requirement count.
If the Sierra Madre Martini perk has not been gained yet, it is best to do it before completing this quest, otherwise one will not be able to get it without the use of console commands.
The ruined store can be used as a substantial shortcut to the objective. The Courier can access the store from Puesta del Sol North by getting to the rooftops, then heading back towards the entrance to the Villa, where a tree with an opening in the wall behind it can be seen. The Courier can walk across the top of an archway over the road and jump into the tree, and from there to the opening, where one will find the doorway to the store. The store connects to Puesta del Sol South right next to the objective.