I've NEVER seen that much rust. Granted I don't see many rusty w123's period...but I do see some from other areas. That's neglect. That's rust that started and over years formed into a hole and nobody bothered looking under the hood or under the wheel well. I would hate to see how much other rust like this there is on other parts of the car.

I'm glad they don't let people drive around with stuff like this because it could be a potential death trap to you or someone else on the road. So even though a proper repair may be costly (or not worth it), count your blessings, because it may have saved your life!

I would suggest taking off the fender on the corresponding wheel well with rust and seeing what kind of rust is under the fender. There's a chance that the rust might NOT be structural and can be patched (though it has to be done well by a professional)

Once the fender is off, you're going to find MORE rust. you can get use one of the 3M "paint and rust stripper" wheels on a drill (given that you probably don't have a shop) or take it to a hot rod shop in your area who can use something called a "needle scaler" to get rid of the flaky rust.

Some cars are not worth saving, but good luck if yours can be saved, and don't cut corners!