I’m so sorry to hear that you lost your dad in such a sudden and shocking way. It is common for the anniversary of the death to be a particularly difficult time, and it sounds having the inquest coming up is making things particularly difficult.
I’m glad you’ve found this site, and I hope that you get some helpful replies from people who’ve been through similar experiences. @HelenL has mentioned in this recent post that there was an inquest into her mum’s death - I’m tagging her here in case she has any insight to share.
We also had this post a few months ago from @Randomhero about going to the inquest into their father’s death: Missing my father.