Of course it's your job to offer suggestions to a director, especially if asked for one. You're the expert in cinematography after all.
You base lens selection on so many factors. Personal taste is one -- maybe you or the director has a leaning towards long or short focal lengths for personal aesthetic reasons.
You base it on compression of perspective. Do you want to elongate the space or collapse it?
You base it on how close you need to get to the subject and how tight.
You base it on the limitations of your lenses, speed, minimal focus distance, etc.
And you try to make a lot of these decisions based on the story point you are trying to make, the mood you are trying to create, and how to best capture the action of the scene.