[Average Joe]

That dont look pretty. Pretty sure you are gonna open a can of worms when you pull out the old windshield. There are a lot of ways to "fix" this. Probably the right way would be to remove the outer truck roof and replace. Then patch in the inner with new metal. I have seen others treat the rust and apply fiberglass filler. Obviously not a long term or structural fix though. Either way, good luck!