My elephant bush is in a part sun/part shade area, so even if it gets the awful heat it survives, I just notice that they seem to go dormant, which I think is a coping mechanism to conserve their resources.
I have a similar plant that is wrinkly right now, but I am ignoring it, just following its usual regimen. But then again, we have different humidity conditions and my potting mixture is different from yours. From what I have seen with my wrinkly succulents, at times, they do that, then once favorable conditions return, they will plump back, but I still observe not overwatering, that is still a major root rot situation in the making, since their rooting system is very shallow, and they can only absorb as much. The roots really need to dry out too. So I think for now, find them some shade or create the shade like under an umbrella or an old curtain as shade. There is a topic on the gardening tips thread discussing home made shade. See if it is something you can do.
I remember we did have a week long of extremely hot hot triple digit heat in 2006, I think we went to 107 very dry heat, even under shade it was just too hot for any of my plants, succulents or otherwise, so I ended up having plants with burnt tips, but as the weather improved and cooled, the plants recovered slowly. Just one of those days where Nature has the trump card.
