Hi. Thanks for your query. Since your partner is having Cholelitiasis, Grade I prostatomegaly and mild fatty liver, he needs a surgery to remove the gall bladder as there are no medicines for the removal of the stones. Since you have asked for the causes: Cholelithiasis mean formation of the stones in the gall bladder. The exact cause is not known, it is thought that during the concentration process of the bile in the gall bladder the imbalance between the three factors which make bile causes this; another causes are Typhoid fever, infection and so on. The Prostate is enlarged as a normal physiological process in elderly adults. The fatty liver is caused by the accumulation of the fat in the liver and can be treated with diet control of fatty foods and exercises.