She is in a vulnerable state but that does not mean that she will spread her legs for you and will entertain you so you have to be very careful in this regard. However, you can consider this is the best situation where you could lay your plan to be with her in an intimate relationship. How to approach her is the question you should answer yourself and have to act as per the situation demands but you should make her first comfortable with you and get her to have conversations with you on the personal level first.
Start showing your interest indirectly in her and see her reactions. If she reciprocates then you can take it from there and may try to get closer to her but if she shows hesitation and she does not want to be with you on that front then you should understand it and you should respect her decision. There are chances that she does want to be with you and vice-versa so try to explore the situation in the best possible way.
Strike up the conversations with her and hear her stories. Be with her and make her laugh and comfortable with you and when you feel the right time comes, you can reveal your feelings for her. If I were in your place then I would become her best friend before approaching her for sex and will be ready for rejection too as it is her right to say no.
List out the series of questions to keep the conversation going and ask one by one question so she can get close with you. Let her know that you care for her and you do not like her to be in this situation and you are ready to help her in possible ways. Do not forget the famous saying that men give love to get sex and women give sex to get love so you should understand that all women are in need of emotional support and in search of true love.
Therefore, if you are able to be her shoulder to cry on then I am sure in return, she will give you what you are longing for. It is not an easy thing to cultivate as you need proper planning and patience to make it happen. Keep in your mind that all the things get back to you in an unfavorable way too and you will be in a great embarrassment.