Hi, as the title reads a Toyota tech spotted two suspicious areas on the frame rails near where the underbody tie bar, or x-brace (whatever it’s called). The area looked like a heavily corroded spot on the passenger side. When he tapped it with a hammer it crumpled and you could then see a clear hole through the frame. There was one more spot on the same exact area but mirrored on the drivers side. When he tapped it the hole was mush more circular but again, seem to crumple clear through. See the two pics I took. Sorry this is all I have for now.

Two questions:

1) how bad is this and what should I do to fix it? I took it to a frame/custom shop this afternoon and the frame guy was a little perplexed about this next question…
2) do the frames of our 4th gens have two walls as the rails transition from the straight side of the car up along where they curve toward the front? When I stuck my finger in the newly made holes, you could feel two distinct walls. One was the hole and then it seemed like an entirely different frame underneath the frame. The frame guy wasn’t sure if it was built that way or if a previous owner tried to weld in a frame kit to hide the deteriorating frame.

Has anyone heard or know of what I’m talking about with the two distinct walls? Sorry that’s the only way I know how to explain it. Maybe I can get better pictures. Any opinions or insights are welcomed. He thought the car was safe to drive for now but recommend welding and entire rust remediation with new coating on the entire frame. He quoted $3-4k.
Thanks

Attached Images