Discoloured lithops

[Succerpunch]

This guy suddenly went from brown to white a few days into keeping it in direct sunlight for two to three hours. Since then I have stuck to keeping it in a shady place. Is it sunburn? Even the base has gone from green to a yellowish-green colour. Apart from a little sprinkle more than a fortnight ago, this has had no proper watering yet. Am I supposed to give it a good drink now? Also, it feels sort of soft, not firm to touch. What is wrong with it? Please advise!

[Jangaudi]

Direct sunlight can cause a bit of a shock if the plant has been shaded, or behind glass before that. However, as they need their summer dormancy and if temperatures are hot already where you are (given you are in the northern hemisphere) you might as well let them start to shrivel already, so barely any water until the fall, and a partly shaded spot. Here's all the info you need :
http://www.lithops.info/

[bbarv]

Sorry to say and be happy to be wrong but it looks ‘cooked’ to me.

[greenknight]

It's not totally bleached out, might be a chance of recovery - but I agree with bharv, looks kind of cooked.

[Succerpunch]

What can I do to encourage recovery? Should I tear off the papery sheath? Also, should it live(fingers crossed), can it survive till fall without any watering at all?

[Jangaudi]

What can I do to encourage recovery? Should I tear off the papery sheath? Also, should it live(fingers crossed), can it survive till fall without any watering at all?

I would not tear off the old leaves, the dry old leaves are actually an extra protection during the hot summers. You do not need to stop watering fully from now, you could fade it out a bit in the coming month, considering it got a sun/heat stroke. Also if you put it outdoors during the summer, but best a bit protected from too much sun, it will benefit from fog and night time condensation. If you keep it indoors, a bit of light misting once in a while won't hurt.
Whether or not it will survive is only written in the stars It will be fall before you could be sure I guess.