Ficus is not that easy to kill. You can try to take it out of the pot and examine the roots. If the roots are still alive, then cut off the dead roots, repot in the same size pot. If you are using the same pot, clean it with bleach first to kill any harmful fungus or bacteria. Make sure your pot has a drain hole and repot in bonsai media not potting soil. Do not over water or let the plant sit in a saucer of water, and do not change the location. Ficus hates having its' light changed.
Happy gardening in Hawaii. Gardens are where people grow.