Besides the head and brain does a neurologist also deal with neck cancer and all?

The "NEUR" in. Neurologist deals with nervous system, central: brain and spinal cord, peripheral, all the other motor and sensory nerves in the body, and autonomic (sympathetic and parasympathetic) - swallowing, heart beat, bladder and sexual control. And neurosurgeons operat on these tissues when needed.More than brain and neck, whole body nervous system and diseases.
Possibly, if… The head is also involved; otherwise an ENT (ear, nose, & throat) specialist & an oncologist (cancer specialist) would be the ones dealing with the cancer. A radiation oncologist may also be involved.
No. A neurologist is not trained in cancer treatment (except a minority who are neurooncologists) head and neck cancer is cared for by ENT surgeons, radiation oncologists and medical oncologists.