Is it normal to notice forgetfulness and imaginary thoughts in a Parkinson patient?

Hello doctor,

My father has been suffering from parkinsonism for the last one year. In the last seven days, there has been a drastic deterioration in his condition. Along with increase in the trembling of hands, the gait has changed drastically. He is no longer able to walk freely, he drags his feet and stops suddenly, which is followed by jerking of the limbs. He stoops forward all the time and any effort to move sends him out of balance and he seems to fall forward. Along with this scenario, he seems to have passed into a delusional world, speaks to himself and makes imaginary frantic hand movements at times. He talks incoherently and seems to have lost the sense of time. He forgets his meals and I have noticed that he tends to make a minute opening of the mouth when taking food. He is presently taking one tablet of Syndopa plus in the morning and a half tablet of the same in the evening. He also suffers from diabetes, hypertension, hypothyroidism, benign prostate enlargement, and obesity. He is 75 years old.

He is currently on Eltroxin 75, Raciper Plus, Franxit, Glipon MF, Starcad T25, Syndopa Plus, Amaryl MV1, Diavit Plus, Flodart Plus, Tonact 20, Ecosprin 75, and Softovac SF.