as u explained your father's present condition, he definately still requires physiotherapy
. because when he last left physiotherapy sessions he was not completely independent. and now due to lack of exercise his muscles are again going back in to weakness. muscles tone also has to be checked whether it is tight or flaccid. and accordingly physiotherapy exercises will be given. so i would suggest you to go to the physiotherapist nearby u who specialises in to neuro rehab he/she may help you definately. for him continuiing exercises is extremely important.