Wakati mwingine ni vyema kukubali makosa. Hakuna kitu kama hicho:
has been died! ...he
has been dead (nadhani ndio sahihi).
Soma hapa kidogo: (English forum)
You can write:
My father
has been dying for two years. (i.e. He has a fatal disease and is very sick, and the doctors say he has not much time to live.)
You can also write:
My father
has died. (He died recently.)
Dying is a one-time event. It cannot happen for two years.
Studying grammar can occur over two years. It takes a long time to learn grammar.
To be dead means not to be alive. Someone can be dead for a very long time.