This cancer has a standard treatment (all patients with it get the EXACT same treatment) and is curable in like 98% of cases as long as it was detected early. Since it is fast growing, it generally is detected early since the growth shows up quick. Often, in the neck or shoulder area a golf ball sized cancer growth appears over the course of a few days... so hard to miss. This cancer kills you in six months, but is one of the most curable. A decade or so ago, this was the diagnosis that led to "celebrate christmas in July" type of recommendations from a doctor.
He'll be fine.