Nicki - I don't know about hallicinating on Erbitux, but I have heard of people seeing/hearing their passed on pets. So maybe your Dad really is seeing and hearing her and she's just trying to comfort your Dad. You could ask the doctor about the Erbitux in case it's important that he know about what seems to be hallucinations, but if seeing the dog is helping your Dad to cope, then maybe that's a good thing.