Googled and attached what came up, as long as the air entry days are correct all good, I reckon that's how he would come from New Zealand where he is now.
I have a Non O visa based on marriage to a Thai and there is no requirement for health insurance, other than Covid insurance, if I leave and return to Thailand, as was the case in May this year, after spending three months in Australia.
Make a fully refundable booking with Booking.com, or another on line booking system, that offers this option. Just make sure of the booking conditions (ie) no prepayment and refundable. You can then use the confirmation and cancel later.