all entries are at the discretion of the IO. But you have options. You're over 50, apply for retirement visa with the relevant paperwork. Apply for a tourist visa, and make sure you have accomodation, money, and a ticket to leave within the permitted time.
if you have the required documents needed you'd be unlikely to be refused. If there was an item they needed they would ask you to send it. Very unlikely to be refused.
He's been coming to Thailand for 13 years on visa exempt ( no visa)
Over 40 visits.
Immigration told him to get a visa and not try to enter visa exempt again
He's worried about losing the visa application cost.
So.. advice would be, apply, carefully check it's been done correctly, wait for approval, have accomodation booked, cash, and onward ticket to leave within the permitted stay.