back from christmas vacation - plants looking sick?

well, i returned home after 10 days at my parents' place for christmas. my plants are at day 42 of flowering. lots of the leaves are brown and crumbly. i know that towards the last few weeks of floweing, leaves will dry up as nutrients is transfered to the buds......but, this looks worse than i think it should?
while i was gone, they were watered once by my friend. before i left, they looked like there was maybe a tiny bit of nutrient burn. so they were given two waterings with only tap water, adjusted to ph ~6.5 yesterday, i put them back on nutrients (1.5-4-5).

are they really sick? i don't know how they could get so much nutrient burn when they have had only water for the past 10 days.

please help.

there is noone who has any advice about the condition of my plants???

how long did they go without nutes, water...etc

i gave them water/nutes on dec. 17th. noticed small signs of possible nute burn, so watered with plain, ph 6.5 water on dec. 21, and dec. 27th. watered yesterday (jan. 1) with nutes.

from the pics, it doesnt look like nute burn. what medium do you use?? if its soil, what kind of nutes do you use and how much??? you may have mad salt build up in the soil which will clog the root system. this happens from natural build up of certain nutes in the soil. if you think this may be the case get some bush master. the kind i use is clearex by botanicare. are the leaves brittle?? did you check for pests? if it is nute burn, (which i really dont think it is) its the worst iv seen it. normally nute burn only attack the outer edges of the leaves, not the center. are your lights on a timer? could they have been burned or dried out by your lights? whats the humidity at? sorry for all the questions, but there are many possibilities and nute burn is at the bottom of my list. your to close for failure to be an option!!!

Botanicare : Product Overview : Nutrients

DUDE I have had the before and would recognize it anywhere you have an official case of nute burn/lock. What your grow median you need to act quick to save it if its possible. that will only gets worse untreated and it destroys a plant quick. Good luck