"As of now, the IRS allows $69 per day in the continental United States. Keep in mind that you’re only permitted to take this deduction while traveling a distance that requires you to sleep or rest away from home."

From: https://www.rivierafinance.com/finance-blog/tax-deductions-for-owner-operator-truck-drivers/

The disqualification for lodging per diem assumes your client is a more than 10% shareholder.