Any money that your employer pays you is just additional wages, the same as if they gave you a raise or a bonus. It should all be included in your W-2, and it's all taxable income. It doesn't matter why they say they are paying you the additional money. There's no such thing as a donation from an employer to an employee. Your employer can deduct all the wages that they pay you as a business expense.
You might be eligible to claim a federal tax deduction for interest that you pay on your student loan. The deduction is based on the amount of interest that you paid during the year, not the total amount that you paid. It's what's called an "above the line deduction," not an itemized deduction. You do not have to itemize deductions to claim it. Here are links to some information about the student loan interest deduction.
Can I claim my student loan?
Topic No. 456 Student Loan Interest Deduction
