Sad

I live in a suburban street. I occasionally see my near neighbours as they come and go from their houses, most have faces I would recognise but I don't know many of their names. When I moved here three years ago I knocked on a few doors and introduced myself. I have tried since to build relationships and get to know people. But there is one couple, almost directly opposite my house, to whom I had never spoken until earlier last month.
I had noticed, with increasing frequency, visits from the ambulance crews but had no idea what might be wrong. Eventually it got to the point where I took my courage in both hands, crossed the road and rang the bell. I introduced myself and was invited in. We chatted and I learned that they were a German Jewish couple and had arrived in England, separately, just before World War 2. Her husband was elderly and now weak and frail with recurring health problems, hence the regular dashes to hospital.
I have dropped in a few more times since, just to say hello and to see if there is anything they need. I only met the gentleman once before this week and I met him again on Tuesday. He was bright and lively, bemoaning the waste of everybody's time that his frequent collapses were causing, he did not want to be such a burden. As I left, I wished him well. He smiled broadly, and clasped his hands to his heart. He thanked me for my good wishes and said that he would hold onto them.
This morning, their next-door-neighbour called to let me know that he died in the early hours. She, along with his wife, had helped him into the ambulance in the night and he had cracked a joke about having two ladies on his arms. He died peacefully, in clear mind and without prolonged suffering.
I know that his wife has friends there with her and I know that a Rabbi will be coming today. I have barely begun a relationship with them and yet it doesn't seem right to be normal this morning. Laughter or light-hearted blogging seems out of place. I am inexperienced in the ways of mourning, of what is appropriate and right at such a time. This is compounded by the fact that they were a devoutly Jewish couple and I am unsure as to what is culturally correct; I would like to take a cake but I'm not sure about Kosher regulations (although I guess the internet would be a good place to start).
I feel very sad. I keep stopping by the window, staring at the house, wondering at the grief and shock on the inside.