IIRC, the first robot to take care of elderly (by making them feel better) was a cute little white furred seal pup. Dogs and cats can do it too. So that's not an argument for a humanoid robot. It *is* an argument for a robot that at least *looks* cuddly.
OTOH, would a robot dog be trusted if it tried to give the medicine? No hands, so all it could do would be spit it out.
For general purpose use, I think the humanoid factor is better, but probably best to stay on the far side of uncanny valley. Two specialized forms seen optimal, one aiming at "cute" and one aiming at "strong". The "strong" one would be for things like helping a patient out of bed, etc. The cute one would be for encouraging obedience..."It's time for your medicine." I suppose the cute one wouldn't need to be humanoid, but it *would* make things easier. And the "strong" one needs to avoid seeming threatening.