To achieve those conditions for text in the Diagram Boxes you need to focus on the Diagram Text Scheme.

On the Diagram > Options > Text tab, choose a Text Scheme that is close to what you need.

The default Birth, Marr, Death is probably a good choice.

Use the Clone… button to create a copy that you can customise, and call it perhaps Deceased Birth & Death.

Now use Edit Text Scheme… so you can edit the Items you want to be displayed in the boxes.

The first thing to do is delete the Baptism, Marriage, Spouse Name & Burial items by clicking the X Delete button lower right.

The next step is to make the Birth item conditional on the person having died.

So select Birth and click Edit below, then change the Template to the following:

=TextIf( Exists(%INDI.DEAT%), FactText(%INDI.BIRT%,"CT","E_Born: _ in _"), )

In other words, only if a Death fact exists should the Birth fact be included.

Finally, click OK three times and that is your conditions

Whenever you want that box text select that custom Text Scheme named Deceased Birth & Death.