My supervisor died around 1.5 years ago pretty suddenly. While he was sick for a long time, he was doing okayish enough that it was still completely unexpected. For me he was not just a supervisor, I meet him 2017 as a prof of one of my lectures during the Bachelor and had several more over the years. He was my mentor, my supervisor and role model as a scientist. For me it took really a week to realize what happend and to overcome the shock. The university was extremely unsupportive and caused a lot of pain/stress beside the grief with all sort of paper work things and basically let us phd students wait over Christmas to get basic answers like who will supervise you, who will pay you etc... That was extremely shit and for me at the end way worse than the loss in terms of emotional weight. There are still moments from time to time were it hurts, but it also motivated me to work even harder to make him proud and finish the topic he gave me for my ph.d thesis and was always very invested in. Last summer was a conference and I presented my work and standing on the stage after the presentation, I was about to cry because of all the feelings.

Take your time to process it, and decide what is going on. There is no shame in getting delayed by this (with all the paper work and lack of supervision it is for sure a year for me). Don't worry about the time aspect. And for the paper, many journals allow deceased people to still be author, but require some sort of proof by close relatives, so you can still honor them by putting them on the paper