In addition to the abilities granted to them by the rings, Black Lanterns retain any superpowers they may have had in life. If the ring bearer's body is severely damaged or destroyed, the black ring will partially reconstruct the body, restoring it to a working state.
Black Lanterns maintain their pre-ring abilities even after acquiring the rings.  If the wearer's body suffers severe damage, the black ring can partially rebuild it, bringing it back into working order.