Hallucinations, Water Retention, Forgetful, Slurred Speech, High Blood Pressure, Diabetes. Diagnosis?

My grandfather was admitted to a hospital for about 3 weeks and released just today, they dont know whats wrong with him but he has vivid hallucinations , is retaining water, is forgetful (often forgets what he was going to say in the middle of a conversation) , is weak, talks like his tounge is swollen , is dizzy , fatigued , cold , has high blood pressure and in iffy appetite he has the worst form of diabetes and he woke up in the hospital must have lost 2 litres of blood we are guessing from his rectum and he shakes alot, please could you help atleast try to diagnose some of this or atleast give me possibilities