Thanks for your question on Healthcare Magic. I can understand your concern. Since your father is having terminal CHF (congestive heart failure) with pitting edema, possibility of fluid accumulation in the body is high. This can cause dilutional hyponatremia (low sodium). Sodium is very important electrolyte for brain equilibrium and function.. So hyponatremia is known to cause disorientation, slurred speech, hallucinations, confusion etc. So better to get done serum sodium level and if it is low then give him hyper tonic saline (3%). Once his sodium level is normal, he will improve in confusion and hallucinations. Hope I have solved your query. I will be happy to help you further. Wishing good health to your father. Thanks.