Thinking about your job and career is a very complex process so having someone there to guide you can be very helpful. I have been in this field for years and I can tell you the most important thing is to listen. It is very natural to want to offer advice based on your experience and knowledge, but sometimes the most helpful resource doesn't offer anything but a ready ear to allow someone esle to process what they think.
I would encourage you to take things slowly. A lot of people feel an urgency to decide what they want, or an anxiety about not knowing. You want to be supportive and know that often times these conversations can be very overwhelming. There are thousands of different jobs and companies out there so individuals can quickly feel lost in the market and sometimes discouraged.
Before we open things up too much the place I like to start is with a person's interests or hobbies. What do they enjoy doing? What classes do they most enjoy? What are they good at?" Not everyone can turn their hobby into a successful career, but this is a great place to start to understanding the type of work someone would enjoy. This can start as simple as "I love trying new foods" and "I'm good at sports" but try to help them understand why they enjoy these activities and how that could translate to a potential job. Do they love trying new foods because they are adventurous, do they need variety in their life? Are they good at sports because they have the ability to focus on a single task really well or work really hard?
What do they not enjoy?
It is a bit corny, but if they can answer the typical interview questions like "what are your strengths and weaknesses" then they will be far more successful in finding a job they are good at and enjoy. So many people pursue jobs they think will provide financial stability, when you can actually make a lot of money in any job (if you work hard and develop your skills).
Last thing. Be realistic but also be very encouraging.
I hope this is helpful, this is a question that could take a whole book to answer. Everyone's journey is different, but this is how I would start.