After verifying that the person isn't just venting and looking for empathy, I'll put in my plug for learning about the transtheoretical model of change [1]. Step one is determining whether the person even sees a problem. If they don't, you can ask questions about what would things look like if there was a problem. But there is no point in giving advice until the preparation or action stages. Before that your best avenue is asking the right questions (see motivational interviewing [2]).
[1] - https://en.wikipedia.org/wiki/Transtheoretical_model [2] - https://en.wikipedia.org/wiki/Motivational_interviewing