I received this plant after a family members funeral service. I placed the plant in my vehicle and it was rather hot out, around 85 degrees. The plant was left in my car for a few hours before I was able to get it home. On the side that was closest to the window a bunch of the leaves had turned to brownish black and were droopy. I do not want to loose my lily, unfortunately I do not have a green thumb so Any advise would be quite helpfu!
These are very resilient plants and this one should bounce back and be back to normal health soon. They dislike direct sun and what i believe happened is some of the leaves were burned.
Plants like the peace lily are strong determined things that prefer to be left alone in their ideal conditions. The best thing you can do is place the peace lily in it's ideal environment, water it when it needs water and let the lily do the rest.
Ideal environment includes minimum bright light. They like to see light but not feel light, so keep it away from direct sun. Keep the plant watered but do not over water. The leaves will tell you when to water, they will start to droop a little. Over time you will get used to a schedule maybe once a week, or 10 days depending on the size of the plant, its root structure and size of the pot.
The plant will let you know if it is getting to much water/sun etc. Right now it is just upset it received too much sun, but it should be fine.
Just cut the dead leaves back and provide water. This is one of those plants that look good with enough water and wilt and look dead when dry. See my answer here and here for more details. A one time incident with hot temperatures and not enough water will not cause lasting damage.
I used to take care of these on a commercial basis when they were in 12" diameter pots. Water them once every two weeks with three or four litres of water...no problems in low light.