Parkinson related issue. This situation.

My father left hand is shaking from couple of months & numbness in left side and while talking sligth changes in tone from 2 days, visited a physician and said its Parkinson diseases & advised this below treatment Pan 40 once before breakfast Atrova 40mg once at Nigth Ecosprin in Afternoon Tab Strocit Plus twice a day Tab Etrobax for pain Taking this from 2 months but there is no improvement so physician advised Tab Pasitane 4mg but we couldnt find 4 mg so giving 2 tablets for 2mg each & doctor advised once at nigth, due to some misunderstanding we gave twice a day 4mg each and from that time we noticed his hand stops shaking but he is forgetting things, talking to himself & looks confused. Is it because of overdosed, I searched online many doctors giving 2 mg, we should give 2 mg or 4 mg. Now we thougth of stopping that pasitane for few days & then start only at nigth so confused should we go with 2mg or 4mg. Kindly advise what we should do in this situation. Thank you