Your father has had an heart attack
.it is very important for him to continue few cardiac medications which would help prevent further attacks called secondary prevention and also to maintain a good function at present.As far as the psychiatric medication are concerned he shouldn't stop them abruptly unless advised by a doctor.
Kindly revisit your cardiologist and psychiatrist
regarding the medication changes.
You have to be brave and patient from your side to help him out. All the best.