This is going to sound like a dumb response, but start with adjusting the color balance. I'm assuming your friend knew enough to do that, but worth a try anyway. It's my understanding that plasma failure involves fading and burn-in, not odd hues. Although I guess faded reds would look pink, but not the whole screen. Do whites have a pink tint on the screen?

__________________
1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)