It would be better if the employer reduced his salary and paid him $1500 flat. Or if the W-2 would have the $1500 figure. That way the income would be reduced, resulting in lower tax. No deduction, but you aren't taxed on income you never get.
As is, if the W-2 shows the effect of $2000 gross, then the expense is an unreimbursed work expense which is an itemized deduction subject to the 2% rule. You will get some deduction depending on his income and other itemized deductions but at best it will be partial only.
Really not a good way to do this.
