Why he wanted it sealed until after a year after his death? That I don't know.
If I was 108 years old . . . and wished to avoid a huge amount of traumatic conflict in my closing days, I’d have been tempted.
My hunch is that The Lord told him and expected him to share it. I don’t know that The Lord insisted he do so while alive.
Doing so while alive would have been far better, imho.