It looks like a Lipoma
,swelling arising from fat tissue.
Nothing to worry.
It is not Cancer.
Please consult a Surgeon ,get it removed and send it for histopathological examination(Biopsy
).You will get the exact diagnosis.Removal is a simple out patient procedure.
Wish him good health.
If you come back after biopsy report,i will clarify further
Wish him good health and speedy recovery