There are two types: a forbidden announcement and a permissible announcement.
Announcing someone's death means informing about a deceased person. It can be permissible or forbidden. It is permissible as a way of informing: so-and-so has died.
So-and-so has died, he will be buried on such-and-such date at such-and-such place, condolences are at such-and-such location, this is an announcement.
This type of announcement is allowed, there is nothing wrong with it, it is permissible. The second type is mentioning the virtues of the deceased.
Saying so-and-so was this or that, this is prohibited.
This is from the forbidden announcements that the Prophet ﷺ prohibited, so this is not allowed.
This forbidden announcement is not allowed, and Allah knows best. Alright.
No, this is wrong, this is a mistake. Except if it is to make things easier for the family, saying, inshaAllah, the man was good, inshaAllah he was such and such, there is no problem with that, but to sit and explain and so on, this is not allowed.