The plant will not survive much longer without receiving any sunlight for photosynthesis. It's probably living off whatever food reserves it has but will continue to decline unless you move it to a window or put it outside (shady location) for the summer. Water as needed to keep the soil a little on the dry side as this is somewhat of a succulent. Fertilize about every 2-3 weeks with a standard houseplant fertilizer following the directions. This is a short day plant that won't flower unless it receives less than 12 hours of light (similar to getting a poinsettia to bloom) in the fall/early winter. If you leave the plant outside in the fall prior to a frost, it will get enough natural short days to trigger the flowering. The other way to force this is to place the plant in an area that doesn't receive ANY light from 6 p.m. to 6 a.m. each day. The location should be cool if possible. Return the plant to a sunny location during the day. At this point in time, you need to get the plant into some sunlight.