Sorry to say, but this plant may be too far gone. You could try snipping off the top, back to some green stem, but its not likely to be successful. We notice that its in a large pot for the size of plant, so it could be a root rot issue (way too much moist soil around a very small root system). If you want to try, we recommend you also take the plant out of this pot and put it in a 4inch (or at most a 6inch) sized pot with well draining soil. Only water it in the smaller pot when the top 1/2 to 1inch of soil is dry and allow a bit of drainage every time. If the plant begins to grow and fill out the smaller pot, then you will increase water gradually to accomodate the growing root system, eventually transplanting it into a larger pot (about 2-3 inches larger than the first pot). This plant will grow in full sun, but don’t shock it (burn it) by moving it into a full sun/hot location all at once. Gradually move it into full sun, and realize that when growing in sun, the soil will evaporate more water, so you will want to make sure a small pot gets watered properly, as needed depending upon temps.