Daughter lost her best friend unexpectedly yesterday

I’ve never posted or been to this subreddit before. I apologize if this has been asked a million times already and certainly hope it doesn’t trigger anything in anyone. My daughter (14) lost her best friend (15) yesterday. These two have been inseparable since 2nd grade. When she wasn’t spending the night at our house my kid was spending the night over there. Played sports on all the same teams and do competitive dance together. We got the call yesterday morning that her friend had passed sometime in the middle of the night. The overwhelming thought is that it was medical and we have no reason to believe otherwise. We are absolutely heart broken as we loved this girl like one of our own but I’m also so scared for my own daughter now. I don’t think she would ever harm herself but I’m also sure she’s never gone though anything like this and while many many people do not yet know something happened, once they do they’ll all think of my kid. You never saw one without the other and everyone associated the two together. We found out when the girls mom called us immediately after finding out about her daughter’s passing. She called us to make sure our daughter was ok because she assumed they were together. In reality it was Valentine’s Day and both went on little dates with their own BF’s I believe. I know this is long winded and I’m sorry, I’m in shock and still trying to process. I guess the advice I’m looking for is regarding how to make sure my daughter is able to navigate this tremendously hard time and what we can do to make sure she’s ok. This might be an impossible ask but I’ll take anything. I’m hanging on by a thread and just trying to be there for her but everytime I even begin thinking about what’s happened I lose it. Sorry for the rambling.