In the question, "Would I take friendly fire damage if I had a mage as companion?", we learn that followers can deal friendly fire damage to the player character.
So, how do I prevent followers, conjured/reanimated creatures and other allies from dealing friendly fire damage to the player character, or improve their AI to avoid them hitting the player character?
I'm playing on the PC, so console commands and mod solutions are welcome.
Note: I'm talking about preventing friendly fire damage from allies to the player character, not the other way around. I am already aware of console commands and in-game abilities that will prevent friendly fire damage from the player character to some allies.
Best Answer
Since friendly fire (both ways) is on by default with no option in vanilla to disable, your options are either to increase your magic resistances to prevent receiving AOE or splash damage from follower, or if that is not they answer you are looking for, your only recourse is to resort to modding & console commands.
Looking around NEXUS it seems that there is no specific mod that prevents your from receiving damage from a companion, some rumours suggest that this mod available on NEXUS No Friendly Fire has that option, the description on NEXUS however does not credit that.
However the suggestion
found here Useful Console Commands : Elder Scrolls Skyrim apparently
Your mileage may vary as
sifhis the "set ignore friendly hits" function, making the target not attack back if you attack them.However if you can target yourself or make your character the object of that command, hypothically it might prevent you from taking damage if you are to believe skyrimelder
Additionally:
To avoid dealing friendly damage to companions from AOE or splash damage, there is an ability called Companion's Insight found in The Elder Scrolls V: Dragonborn which has the following description
N.B