What else could I have done on this 2000 Mustang?

[Stokdgs]

If the pattern of marks in your friend`s Mustang paint look like the pattern in that picture, regardless of whether you can touch them or not, it is paint failure coming down the pike..
Nothing else makes that pattern except paint failure..
Dan F

[Accumulator]

Just FWIW, even "failing" paint can hold up surprisingly well for a long, long time if the vehicle is pampered a bit. My `93 Audi has a lot of areas that I expected to get really bad but they`re no worse than they were when I got it back in `08. And some all-original collector cars have had crow`s feet/cracking for decades.