Having lost my father to cancer when he was far too young, I can sympathise with you. Love him as long as you have him and I hope that you and your husband have a long and happy life together.
I'm sorry to hear that you and Leona's friendship is suffering through this. People react to life changes in strange ways sometimes. Perhaps someday things will be different, but if they don't then I hope you can forgive her anyways.
Peace on your journey.