Dracaenas are especially sensitive to fluoride and chlorine in the water and the browning may be due to this. Chlorine can be eliminated from water by letting the water sit out overnight. However, if you water is treated with fluoride, there’s not much you can do short of installing an appropriate filter and/or growing less sensitive plants. It would help that the plant should be in full sun, not part sun. I would also suggest that you repot it into a pot that is slightly broader and has a drain hole. Use potting mix, not garden soil. When watering you should water it until the water runs out the bottom of the pot. Let drain for an hour then put it back in the usual place. Water when the top 2 inches are dry by sticking your finger in as deep as the second knuckle.