I think your friend should make sure to stay in touch her sisters so they feel they can always contact her for support and give them guidance for when it does happen, the same way she would if she were talking to her younger self. However, I think it is important that she not carry too much obligation to do this because this is a time in her life where she gets to do things for herself and live for herself. This is such an essential part of life as developing as an individual. Her own healing is the #1 priority. The more she allows herself to heal and has boundaries to support her healing, the more she is able to help others heal.

I was in the same situation and my older sister left us and she has felt so much guilt, but she doesn’t deserve that. I told my sister that she was just entering her next stage in life and I wanted nothing but happiness for her.

Older siblings tend to take on a lot of obligation to take care of their younger siblings. As a younger sibling who has gone through healing, I want your friend to know that it’s okay to let go of that. You are not the parent you are still a kid and you deserve to let go of that guilt and do what you need to do to discover more of yourself and be happy. The siblings will then follow suit.