I also agree with Ben. Looks like we've all toasted a phal once or twice in our orchid career.
You think you're doing a good deed and then whopsi, the poor plant is 'well done'.
I've come to a point where I'm no longer very stressed regarding sunburn on phals, but I'll give it to your friend: This is one of the worst ones that I've seen so far.
It looks unappealing and it makes the plant look shabby for years, but as long as the growth point is intact and the roots are there, they do recover from it.
Regarding cutting or leaving... I think I'd leave the leaves on at the moment and keep and eye on them. Maybe they're all too far gone, but I've had several phals with sunburn and although there are cases when the whole leaf dies off, there are also times when the affected area just dries up and leaves the rest intact. You can of course do a test and try to cut of the affected area on one or two leaves, put on cinnamon on the cut edges and see if you can rescue the remaining of the leaf that way. I'm thinking a little bit of leaf is better than nothing, but I could be wrong...