Thoroughly water it, then let it dry out completely before you water it again, maybe put it in your bathroom with a grow light to help it recuperate, or mist it regularly...and give it a little time. Hopefully it will bounce back.

Pumpi,

Here is some specific information about caring for condo mangos from the Tropical Rain Florist Mango website:

If your mango tree's in a pot, check the moisture every week. Stick your finger into the soil, is it damp? Stick your finger into one of the holes around the bottom of the pot, is there moisture at all? Water thoroughly only if dry. The soil should go from very wet to very dry, then back to very wet. And so forth.

DO NOT TRY TO KEEP THE SOIL IN ANY POTTED PLANT OR TREE SLIGHTLY DAMP ALL THE TIME.
Go back and forth from real wet to real dry.

Hope it helps and your Julie recovers!

Here is a link that might be useful: Trpocial Rain Florist Mangos

Thank you! The mango has stabilized. Looking forward when it will begin growing, but at least it has not lost any more leaves.

Excellent! Hopefully it will really take off for you in the spring. :)