Looks like Dracaena marginata.
Unless it's completely rotted, it should grow back. I would unpot, remove all old soil, rinsing it cleanly off. Then trim any too-long, mushy, circling roots, and the tips of the branches down to firm material. Repot with well-draining, non-water-retentive mix, put in lots of light, several hours of direct sun per day. Don't water until significantly dried out (but not yet bone dry.)
Dracaenas are more sensitive to water chemicals than other plants. For this reason, they should never sit in soggy soil, should be flushed occasionally, and tap water may make them ill. If one switches to distilled, rain, dehumidifier condensate, there can be a dramatic difference, healthy improvement, if fluoride, chlorine, or chloramine was making it ill.
