How long will a medicated bipolar manic last for a 54 year old male. He is treated for this the first time and it is lasting already for a month?

Unclear? I am wondering if your question is, how long will a particular medication last? It is not really possible to say without knowing the name of the medication. It is very important, i think, to be in close contact with the person's psychiatrist, especially since you say there are already good results. Best of luck.
Bipolar. Depends on type of medication used and dosage. Consult the prescribing doctor.