My little sister's breakdown

Today I got home from work and found my little sister crying like never before. I went inside the room and asked her what was wrong with her. To my surprise she tells me the reason why she was crying was because she is tired of being without a mom and that she wanted to see our mother. Her reason for crying just crushed me because I thought we were all getting over the fact that our mother wasn't with us and that she is never going to be with us again. As she was explaining to me how she felt about the whole situation I started to understand where she was coming from because I felt the same way when I was her age. My sister is only 17 years old and she is heading to college next year. In my opinion this age is the most important age in a girl's life and that's when a girl needs her mom by her side the most because that's how I felt when I was getting ready to make my decision about college and everything that came with it. She expressed to me that she was tired of seeing all her friends with their moms and talking to them and hanging out with them that she feels like an outcast. "When I go to my friend's house and I see how her mom treats her and how much she takes care of her makes me want to cry" she said. "I want a mom that can wake me up in the morning to go to school and to make me breakfast and also to go shopping with me and most importantly to give me advice about guys and about life which I need desperately at this moment." She added. I told her that she knows that she can count on me with all the advice and help she needs for college and relationships advice but she told me that as much as she loves my advice it's not the same than coming from our mother and at that point I couldn't say nothing because she was totally right. I felt so bad because i didn't know what to do to make her feel better and it really hurts me because I knew what she was going through. When things like this happen that's what gives me strength to be the best that I can be and to show my sister how to move on and be a strong person no matter what because she looks up to me so much and she always tells me that I'm her role model and that just gives me more strength and pushes me to do the right thing. I know that this is something that my sister is not going to get over right away and that she needs time to realize that that's the way it is and that all she can do is push herself to succeed and to show my mom that we did it without her any way. Apparently my sister is having a lot of boy drama and friend drama at school and she wants to talk to somebody older like ''my mom" to give her advice and because she can't do that it gets her upset and depress just because she needs that person by her side. While sharing this bad moment I started crying with her because it breaks my heart to see any one I care about like that and it just saddens me because I didn't want her to go through that kind of pain because it is not a good feeling and since me and my big sister tried and are still trying our best to be a mom figure for my brother and my sister with the help of my wonderful grandmother it seems to not feel like the love a mom is suppose to give you and i understand her completely.