Generally, there is no "quick fix" for fogged windows
Been there. Fogged windows that obscure the rear view mirrors. Others may post their differing experiences with great success with quick fixes, but my experience is that replacement with new insulated glass is the best option.
Quick fixes involve drilling holes into the glass panes, injecting a cleaning fluid between the glass, drying the interior space (air or alcohol or both, generally), and when dry, sealing the holes with a semi-permeable plug. It looks great if the glass hasn't been etched internally by chemical contamination, but the leaky glass problem isn't fixed--just remediated for a while. It will fog again, despite assurances to the contrary, as the desiccant between the panes has been saturated and will never be effective in the long term in its unsealed environment. Because while the glass is unfogged, the cause of the fogging hasn't been fixed.
Replacement ain't cheap. We removed our entire window and brought it to a commercial glass shop. They removed the damaged panes, made new double pane windows and reassembled the window.
We had to deal with the removal and re-installation of the window, but it wasn't anything beyond a common sense activity. If you can flush your black tank without needing a full body shower afterwards, you can remove and install an RV window.
I wasn't cheap, as I said. It cost $200+ each for fogged and failed window pane. But as I say to folks who ask, owning a motorhome home costs money, and fixing foggy windows where you can't see your mirrors is a good place to spend some.
Good luck with getting your windows fixed. I hope you have great (and reasonably priced) success!