URGENT PLEASE ANSWER (Toenails falling off)?

My mother in in the cleaning business, she cleans offices and things like that. She has to wear closed in shoes ('sneakers') Any who, it was a few days ago that she started to notice strange things happen to 4 of her toe nails. I have looked at them and the 'affected' toe nails seem to be tinted slightly yellow, a creamy yellow, and they look terribly dried up. The nails are all hanging from a small piece of alive skin, if she wanted to, she could pull them off easily. She says she feels no pain whatsoever. What could be happening? Also, a few weeks ago, on one of her toes she has bubbles all over one specific toe filled with pus, she's popped them all and now is healed, the only issue are these dried up, slightly yellow, and kinda dead-looking toe nails. Does anyone have an answer and some remedies or medications she should pursue?