Nicki, pallative treatment with Erbitux is probably because he has already been treated with Cisplatin for his concurrent chemo-radiotherapy. Recurrent cancer becomes immune/resistant to Cisplatin.

Your dad's onco might be looking at controlling the disease progression wth Erbitux, if your father responds well - which I am hopeful. The treatment may be followed up with Total glossectomy and re-radiation (to take care of PNI).