Even those adjudicated as incompetent by the court have the right to refuse medical treatment. As long as they can do so, unfortunately, there's really not much one can do about it.
ark2076, if your father is having trouble swallowing and his medications can be crushed, crush the meds and mix them with applesauce. That will make it easier for him to take them. Should he have meds that cannot be crushed, ask his physician if there are other Rx's that can be crushed.
With the increase of elderly population, there now are physicians that make house calls again. This is something you may want to check into.