I am truly sorry to hear about you experiencing a loss from death. I believe your coworker is correct! A loss on its own is enough to be very distracting for months at a time...if not for several years!
But, when you couple that with the diagnosis of alcoholism, well, let's just say that this is a whole 'nother can of worms all by itself. I am by no means an expert on the subject. But, I have known and spent time talking to Adult Children of Alcoholics who shared many of their horror stories with me. They certainly had long term repercussions from their experiences. Something like this would also greatly impact the grieving process.
My heart goes out to you! Be kind and gentle to yourself! Is there anyone else that you can talk to about it? I am a big believer in attending Grief Support Groups. It is a safe place to talk and unburden yourself. Perhaps check with your local churches or community groups?
Keep us posted, Janet. And, please allow yourself all the time that you need to grieve.