I kind of know how you are feeling, as I had a rocky relationship with my father as well. My father was extremely abusive towards me, in fact I would say it bordered on torture at times. The difference is that I was able to have a relationship with my father the last three years of his life.
My father showed such a difference between my brother and I , that it was like my brother was his only child. In the later years, my father did apologize to me, without explanation, for the way he treated me while I was growing up. He often said, in his later years, that he always felt it would be my brother that would be taking care of him in the later years. When my father became ill, (asbestosis and pneumonia) my brother didn't ever call him, and in fact my father passed without having contact with my brother.
Unlike your father, to everyone else that knew my father, he was one of the kindest, mildest, gentlest person they knew. In fact to a few people I later shared how my father had treated me while growing up, some found it difficult to believe, while others refuse to believe it, as they could not comprehend such behavior from this man. This kind of magnified how he treated me, as to everyone else he was so kind.
With all the poor treatment I received from this man, I direct my focus on those good times I did have with him. Although I was a grown man, I was like a child at finally receiving the love I always wanted from this man.
I think you need to do the very thing you mentioned in your post. I think you need to focus on the good memories you do have with him. Even though your relationship was estranged, he was attempting to repair the relationship, he just was not able to finish the journey, because death took him before he was able to complete it.
I don't know you, nor your father, but I am a father of a daughter that I have a rocky relationship with at the present time. Even though I have great problems with the lack of respect my daughter shows me, and I at times am hard towards my daughter, I assure you, it is not because I don't love my daughter. Even though I am aware of not having the closeness with my daughter I would love to have, I realize that my actions are nothing more than my feeble attempt to protect myself from being hurt by her, more than anything else.
The way your describe your father, I would venture to say, he probably had difficulty in expressing his emotions, and like I do at times with my own daughter, his lashing out at you, had more to do with his fear of being hurt, than not loving you. I think deep down you know that his actions just prior to him passing was his way of attempting to repair the relationship he had with you. A will, written at a time when he was hurt and angry, has nothing to do with his feelings towards you at the end.
You can't un-ring a bell, and you can't bring back the dead, but you can keep your focus on the good memories you do have of your father, and at the same time, know in your heart of hearts that if time had permitted, your relationship would have grown to be that special relationship you so wanted with your father. I think partly you would just like some sort of validation that your father did in fact love you.
I can only speak as a father that loves his daughter so very much, but at the same time can't always put aside my fear of being hurt long enough to cherish the time I can spend with my daughter. I think your father did love you. At this point in time, again, all you can do is cherish the good memories you do have with your father. Keep your focus on that, as well as know that he was attempting to rekindle that relationship he did have with you when those good memories you DO have, were fresh.
I don't know if this will help. IT may be more ramblings than an answer, but I will tell you this, your post has opened my own eyes, and given me fodder for ensuring my daughter does not have to some time down the road, question the very things you are having to deal with at the present. Good luck, and may you rest assured that time we are not promised was the only thing that stood in the way of your dream, as well as his coming to past