If you suspect root rot I'd go ahead and unpot it and fix the situation. While this is not the best time to, waiting could kill the plant.

They tend to loose a lot of leaves when they are moved to a new environment. Also, the soil will stay wetter in the winter time since the plant is not really growing. Just let it dry out before re-watering.

Based on the photos you provided, it appears that your Ficus Ginseng is experiencing some stress. It's possible that the plant is suffering from root rot due to the soil being too moist for an extended period of time. However, this could also be a natural response to acclimating to its new environment.

To check if there is root rot, carefully remove the plant from its pot and inspect the roots. Healthy roots should be white or light brown in color, while rotted roots will appear dark, mushy, and may emit a foul odor.

If you do find signs of root rot, you will need to repot the plant to save it. Choose a pot one size larger than the current pot and use fresh, well-draining soil. Gently remove any rotted roots, being careful not to damage healthy ones, and plant the tree in the new pot.

If you don't find signs of rot, then it's likely just the plant adjusting to its new environment. Keep an eye on it and make sure not to overwater it. Allow the soil to dry out slightly between waterings and only water when the top inch of soil feels dry to the touch.

This post is 7 years old, and the images do not reflect a plant "adjusting to its new environment". It appears that the plant was poorly wired (it was undoubtedly sold as a bonsai) and the wire left on for so long that when removed the bark was so badly torn it stopped flow of photosynthate (food) through phloem tissues to the roots. Lacking a source of food/energy, the roots soon died, thus ending the the plant's viability.

Al