i would not be so quick to blame your friend. Citrus can be temeramental indoors and your pot looks huge. Large pots hold m,ore water and delay drying. Yes, it can come back, have had citrus recover from 100% leaf drop.

Thanks! Any tips to help it come back?

Not sure where on earth you are, but I would put it outside once the weather is stable and mild. If the soild is moist, do NOT water until it gets dry and shows signs of new growth.