How can I use a character's attributes to determine another character's attributes?

Hello all! I'm trying to streamline the math for one of my players whose character is a Beast Master Ranger (DnD 5e). Their companion's AC, attack rolls, and damage rolls increase based off of the ranger's proficiency bonus, and I want to call the ranger's PB in the companion's NPC sheet so that those values can adjust themselves as the ranger levels. I'm trying something like this: 13+@{Stor Helder|pb} , where 13 is the base AC of the companion But it only ever shows the whole string and doesn't actually call the attribute. I figure it's a problem with referencing another character sheet, but I'm not sure how to work around it. Any ideas?

I've not found a way around that either. I have tried placing that into the AC, strength, dexterity, etc fields to no avail. Someone else has just told me to make sure they have access to the npc sheet and add it themselves.

Yeah, as I recall for a similar application (5e Druid wildfire spirit) the AC attribute would not accept formulas. You can reference other character's attributes in the attacks/damage fields, though note that the mouseover tooltip will add a strange +0 for no apparent reason.