I did something similar once with a very close friend using audio tape. His name is Eddy George. Eddy passed away many years ago. We both talked in the recording mostly about his life and fly fishing. I can't listen to those tapes, I never have. Maybe someday I will. We did it so our Trout Unlimited Chapter could publish them for those who did not know Eddy, to learn more about fly fishing in the Smokies before it became a National Park. Eddy wanted to pass that information on. I can't make myself do it.
I commend you for your courage at such a trying time. The passing of a good friend is a very sad time. Thank you for sharing your friend's advice. We will all learn from his life and his insight.