I tried to cook three meals a day for my former alcoholic diabetic father in law who was dying of cirrhosis of the liver. He complained bitterly, told me the special diabetic foods I was fixing for him tasted like sh!t, and ended up moving out after four weeks living with us. He got to go home and drink himself to death, which is what he wanted.
You have to realize in a very hard way sometimes that you are not in charge of anyone elses body unless its your own or your own childs.