i can totally relate to how you feel. regretably it keeps it green for us. it reminds us that this fate awaits us too if we don't stay sober. "i have buried" many, many a good friend due to alcohol or drugs in my 21 yrs. sober. it is sobering to say the least. it made me angry too when my bgf in my entire life deliberately took her life. i had been overjoyed when she started coming to AA. my anger was overwhelming cause she didn't call me when she felt so full of despair. i was incredibly sad too. your friend must have seen no way out too tho she was trying to get better. hopeless and helpless. but remember, "many of us do recover if we have the capacity to be honest" with ourselves and others. addiction to alcohol or drugs promises us jails, institutions and even death.
those of us successfully staying clean and sober are the fortunate few.