Help unhealthy plants!!!

I have just returned from holiday and left the care of my Exodus cheese babies (about 8 weeks old) in the care of my friend, I have come back to find some extremely unhappy/healthy plants. They are looking very limp, he said that about a week ago the bottom leaves started to turn really yellow and a few off them fall of completely (he said that they were not really crispy just turned yellow. He told me that he stopped giving them nutes and let them dry out a bit incase he was over watering them. He also said that the temp in the tent got to a max of 34c and he had noticed that one of the extractor fans had stopped working and the two lights were causing so much heat so he moved all 8 under one light to solve the heat problem until i got back.
This is only my second grow so i would very much appreciate some help to help save my plants?

Going to be hard to help without seeing what you got going on there. Take some pictures and post. Yellow leaves can mean a lot of things , we really need to see them to give a accurate diagnosis.

Pictures please, it could be anything from overwatering to nute burn. Its always better when we can see

Sounds like he was just a bit overzealous with the watering, no need to worry! Just let the soil dry completely before your next watering so the roots can breathe!