withering plants..can they be saved??

If the roots are still in good shape the plant will grow back.

Plants are unbelievably resiliant. Even those in horrid condition with a few half-eaten leaves can recover if the roots are healthy and they're given good conditions. Some Crypts melt down to nothing, but if the roots are undisturbed, new growth emerges and the plant keeps on growing. I'm sure a sword can take a little abuse and recover, as long as there are sufficient ferts, CO2 and light.
I purchased some absolutely pathetic looking (spindly, pale, most of the leaves were gone) Rotala rotundifolia from a LFS once, I wasn't even sure what it was, but at $2 a bunch I figured I'd take some home, try it out and see if it would recover. Suffice it to say I'm now overrun with bright pink, fat leaved stems. I was also amazed a little while ago to discover just how tough Hygrophila polysperma is - a leaf must have detached from one of the stems and become lodged behind the spray bar; when I moved the spray bar to clean behind it, I found the leaf - it was busy growing its own little roots! I was curious to see what would happen, so I left it floating in the tank. Two weeks later, it's a small plant with two stems and about 20 leaves - absolutely amazing!

Only if you are able to provide consistent improved over all conditions for the next two months, not just light, but nutrients and C02 as well. If your tank is not well balanced, then it will be much more difficult and slow for the plants to recover. Prune off any leaves that are yellow or trasparent, even if that leaves no leafs on the plant. Stick an NPK fertilizer tablet in the gravel next to the swords.