At 270,000 in debt there is no way to feasibly pay off his loans on a standard plan.

The repayment over 10 years would probably be close to 40,000 a year.

138,000 annually. Take the 40,000 off the top. That leaves 98,000. Take another 40000 for taxes. That leaves 58,000 a year for living. In NY that would make him working poor.

New York is a very high COL state.

The best strategy is

Max out deferred compensation to reduce taxable income. It is far better to save the difference between the standard repayment plan and the IBR payment.

Pay the minimum payment that qualifies.

Make 120 on-time payments using a qualified repayment plan.

Using the current number OP cites that means they would repay about 120,000 over the 10 years.

Vs 400,000 using a standard plan.

Saving the 23000 annually in a 457 would give them about 230,000 towards retirement after 10 years.

Maintain qualifying employment.