I am sorry for your loss. The reason for her death might be aspiration of sea water. Sea water being rich in salt content draws water from the blood resulting in electrolyte abnormalities which might have led to her loss of consciousness
. It also causes pulmonary edema
[ water in lungs] that might have led to froth in mouth. Lack of oxygen
made her turn purple. Elderly patients have poor reflexes , that might have led to her aspiration. hope , you cope up with the loss.