Is my father hallucinating from his medication?

My father was in the hospital in January with pneumonia. After a week's stay we convinced the doctor to allow him to go home because he could not sleep or didn't want to eat much.

After a day at home he improved more each day. He was put on double the dose of Coreg and also a thyroid pill in April. Since then he has seemed to be hallucinating and always talks about the millions he is going to win. He proceeds to go on about all the numbers, codes, dots and lines that have to be lined up and if they are not he gets frustrated and angry sometimes. Always goes on about numbers lining up. What do you think may be the problem?