That looks like nute lock or high soil ph. You need to do a flush. If you have good drainage pour a gallon of water into the pot and let all the excess run out the bottom this flushes all the salts and any other bad things out and corrects the ph. I know this is not a good time to add nitrogen but they are extremly deprived of nutriants because your buddy never used any and it has used up all that was in the soil. So get some mild nutes, this should get them to bounce back in a few days. If you have a store around that sells Fox Farm nutes get some Big Bloom and add that to the water. If you get that I can almost garentee they will bounce back because I have done it with roses before that everyone thought were dead, 2 weeks later they were lush with leaves and producing new flowers.