Depending on the stage of bipolar the medication will take time. Any medication given to treat anxiety, depression, bipolar will have side effects such as drowsiness,  nausea,  Headache etc. Best will be to consult the Psychiatrist who has been treating your father and ask if he would require any counselling.  There are probabilities that the family members might have to understand to deal with your dad, which your Psychiatrist will explain.

I am able to understand your concern. Medications for bipolar disorder take around 2-3wks to start working  in some patients even 4-6wks. And therapy sessions are usually initiated once the acute bipolar symptoms settle down with meds. Its role is mostly to help prevent further episodes from occurring. For further clarifications regarding meds and therapy I would be more than happy to help you with that. You can directly consult with me through Practo. Online chat consultation is also available.