Welcome back Nicole and very sorry to hear about your aunt and her family. Deaths due to drunk driving are far to common and a 100% preventable tragedy unfortunately. I wish you and your family peace in dealing with your loss.
Regarding your question, I personally don't believe that there is a "rock bottom" when it comes to convincing people to quit drinking. Unless it's your own actual death, or perhaps life imprisonment, the consequences always wear off enough to make you think you can drink again if you listen to your addiction.
To me it's more of a personal responsibility issue - as in when do we decide enough is enough and put a stop to our drinking. We are the only ones that can make the decision to quit for good, and we can do it at any time. You could do it right now, this very second if you chose to. You could certainly use this very sad event in your life as a starting point, but even then it's really all dependent on whether or not you are ready to take on the personal responsibility and make things better for yourself.