Mortar touching sheating – GreenBuildingAdvisor

Hello. Climate 2 , 1980 brick veneer wall assembly. I discovered that the mortar in my exterior walls is about 80 percent in full contact with the interior fiberboard exterior sheeting, no wrb. , blocking the 1 inch gap. I have found this in three exterior walls so I’m gonna assume the entire house is like this.  I chipped of alot of the excess mortar but the brick ties to studs also have mortar, is there a spray or liquid I can apply from the interior to prevent moisture from the mortar being absorbed into the sheating and studs ? I was thinking of spraying it  with proscoso  sure klean silane siloxane since  because it’s breathable. And I’m gonna replace the rotted sheeting with thermoply coated in redguard because nothing thicker can be cut and cobbled into place . And I know red guard has a different purpose, but I figured it’s better than nothing.

please, any advice or solutions. Removing the entire brick from the exterior is not an option .