Last week of bloom, plant dying

So i have this plan that has had dark red stems for a while. The fan leafs started drying up and getting lots of necrotic spots. The leafs started to slowly turn yellow. Now the leafs around the buds themselfs have started to go trough the same. What should i do? Let it flower for the planned additional week? Do i risk losing bud? Or should i harvest it now while the buds look alive? The thing is also, i have 5 plants, but this plant is a week older then the rest, and its the only affected in this way. Could i give all the plants 24 h darkness, harvest this plant, and then continue flowering the rest? Im gratefull for any possible help

Your plant leaves will always start to turn yellow over flowering time.
So if you only have one week left you could possibly be all good, some pictures would help though to clearly see what could be wrong..

How many weeks have you been flowering?
Do you know the strain?

I do not know the strain. They are all different. Also, even worse, i do not know how long they have been flowering. But from what i can tell more or less half of the pistils have turned brown, and trichomes seem, from what i can see with my microscope seem to be getting done. Im afraid i dont have a good enough camera available at the moment though.