Sad story, sorry for the loss of your friend, detachment is one of the hardest things to learn in the program, we maintain our own sobriety and support others in their sobriety, but the hardest thing for us to come to grasp of is the only person we can keep sober is our self and the only person who can get us drunk is our self.
We put out our hand to help others recover, but it is hard when someone we care about chooses not to take our hand, the last thing we should do is drink about it because one day they may want to take our hand and we need to be sober to give it.