Upvote:2
Yes, should be fine. He will enter the U.S. under the Visa Waiver Program. This allows travel for up to 90 days and is multiple entry.
Upvote:2
If he's traveling on Visa Waiver Program under ESTA you have approval to enter for 2 years. When going to Barbados the 90 days count doesn't stop so it should be kept in mind