Can I make plants that have turned yellow and droppy green again?

My mum just went overseas a month ago and before she left, she asked me to take care of the plants for her. I ve been watering the plants once a week like she said. But, two of our money tree plants have gone yellowish and droppy. Im not sure what mightve caused it... Are they meant to be kept indoor or outdoor is fine? Is there any way of making them green and healthy again?

You could be keeping the plants in a place thats way to hot and dry ( like near a heater). If your plants are yellow, that means their dead and there's nothing you can do. My advice? Buy new plants for her.