Depends. Is it more than he paid in premiums or less? I think I know the answer.
Part of it will be taxable income for him.
His taxable gain will be the proceeds from the policy less the premiums paid. I cashed in a 46 year old whole life policy a few months ago and the gain was 70% of the cash value.
Did they withhold tax?
The insurance company should be able to tell you the taxable gain. Mine was in the paperwork that I received on the surrender.