How do I make it so a foe can't attack a certain party member if they are wearing a certain item?

As the topic says, I need to know how to achieve this.

It needs to be EXCLUSIVE to one character, as in the foe can attack everyone else EXCEPT the character with the item equipped.

This also needs to apply to a single boss. As in this specific boss can not attack that character who has the item equipped.

Does anyone know how to achieve this?

I think you can make the item have the Sp-Parameter "TGR" property set to 0%.  This tells the combat logic not to target the user equipping the item.

That won't work, since the character can have this item equipped all the time, the character will never be attacked.

In that case, have the boss, in its Turn 0 Turn (Troop tab), assign an invisible State to the character IF the character has the Item equipped.

Said State sets the TGR property to 0. So it will only apply for that battle.

There you go.

And the state would have to be removed on end of battle in that case, or it will carry over to all other battles after the boss.

What do you intend to happen if the boss kills everyone but that one character? Do nothing?