My DM passed a couple of years ago. Sorting out the death admin was a lot of work but it was helped by fact that she had told us where her will was, who the executors were and who benefited.
In contrast my PIL's who are still alive but very elderly and frail are refusing to tell DH the location and details of the will.
AIBU to think that this is selfish as it's going to make it harder to organise things in the future.