Shower valve in cinder block wall has corroded threads

[eyeteach]

Hi folks.
60+-year-old house. Cinder block construction with shower plumbing within outside wall. Threads in valve where stem screws in are corroded beyond usable. Is there some kind of Helicoil kit designed to repair threads such as these? If not, what options do I have regarding plumbing repairs in cinder block? Thank you.

 

[frodo]

outside wall?

nside wall?

1,,nside wall, repipe from the back side, new pipe and valve

2,,outside wall, repipe from the inside build new wall to cover
3.. demo wall, replace pipe/valve/wall

 

[eyeteach]

California.
It's the outside wall and there are no apparent access points either inside or out. I've removed all the ceramic tile in addition to the 1" of stucco applied between the block wall and the tile. During construction, are the bricks slid down over the plumbing then cemented in?
Remember, this is a block wall. How much wall can I demo without compromising the structural integrity of the wall?
Thanks

 

[frodo]

demo the old shower, shower pan, walls everything

build a new wall, install new piping, and valve.

new shower pan, new tile


others may have different ideas,