Sorry to hear on your wife's condition.
A year ago, a co-worker was given his last diagnosis after a year of chemo that just didnt work. His insides were just torn by cancer and he was given a few weeks left to live. A friend of his organized a campaign for anyone who worked with him, who knew him to make a video directed at him and at the 2 young daughters (2 and 4 year olds) and wife he was leaving behind. We all got together, had a private place to record and recorded some thoughts on him. The resulting video was given to him and his family. I dont know if he watched it but for my part I tried to give an impression of who this man I knew was and his influence on me.
It's not easy to ask people to sit down and do this but knowing the kind of people your wife had an influence on and capturing those memories may be another good way to preserve the essence of who she is.