A turn for the worst...woody, Ndica?

Guys, it's a sad day here in Tejas. Everything has been going extremely well....that is until yesterday. I woke up and retreated to my sanctuary, the grow room, to chill the "young adults" my plants. Anyways, I turned the corner and to my dismay my Kush plant was, for lack of a better word, fucked...It looked so healthy and now the leaves appear very dry, unhealthy and the entire foliage is wilting over. The stem is still standing straight and strong at 15" but the leaves are almost hanging straight down. is it too late to save it, and if not what do we do and what could be the problem? The other three plants look perfectly healthy.