So dreadfully sorry for you and your family. It will take a long time for you all to come out of this grieving - and, sadly, feelings of guilt.
24 years ago my youngest son, aged 25 yrs died. accidental death brought about by psychological condition - there are five older siblings.
We gave each other as much love and support as we could, His nearest aged siblings (twins) felt the loss the most, it had always been that three and the older three as another type of group. Both twins accepted counselling offered by their work.
For the first five years the family used to try to meet up and help each other on the anniversary of his death, but then found we did not want to remember that day - and since then it is his birthday we come together - if possible each year.
Even after all that time, there is a gap in our family and all my grandchildren - most of whom were born after his death, know of their Uncle G. Photos of him are in all our homes - I still do occasionally talk to him at times of stress.
Took two full years before I started to come out of that intense grief, and a further two or three years before I did not burst into tears every time I thought about him . Be kind to yourself and your children and allow time - and accept any offer of counselling.
All I ever wanted to talk about was him, and became a prize boor, but it helped me. When I said i would not come to a committee meeting (which had been delayed to allow me to come), one of the nicest thing that was said to me, was by the lady who phoned me to persuade me to attend was 'Come along and bore us'!!!
Remember his life - not his death.