Payroll

Taxes, insurance, and employee benefits 

This is for his employees, not himself, right?

Only the employer portion of Social Security and Medicare tax are deducted separately (in addition to Federal and State Unemployment).  The other "payroll taxes" are already part of wages (which is deducted as wages).

Is the 401k for himself?  Or is it his paying an employer-portion of 401k for his employees?

Workers Comp paid by the employer is an insurance in most cases, but it is sometimes also paid by the employee (depends on the type of insurance and the State). You need details.

If I am being provided payroll by a customer I ask for their W3s, 941s, 940 and TWC reports so I make sure and report expenses correctly.

Add the employer only portion of the 941 taxes, 940 & TWC - enter box 23

enter Gross wages box 26

401K box 14

wokers comp box 15

The employees' deferred portion of their 401Ks is part of Wages and included in gross wages.

The employer's 401K match is Employee Benefits.