Honestly I can see one of the biggest problems being that it has no drainage. Drainage is really important to keep the plant from drowning and οΏΌ dying from over watering. If you plan to move it I would also suggest getting all the dead leaves out of it.
does it seem dry? if so, moving it out of direct sunlight for a bit may help. if it doesnβt seems dry, just wilt, i suggested a new pot with some drainage and make sure not to overwater. hope he perks up soon!