Did he get the stamp Application not approved and 7 days to leave the country?

Sorry, but we can not help you to find the best country to visit and apply there for a new visa that fits his purpose and lenght of new stay inside Thailand.

You can only be inside Thailand using 1 visa, so you leave Thailand, apply for the Thailand pass etc due to covid, and on arrival you stamp in using the visa you wish to use until you leave.

You can apply, but as it is mentioned no more Extension of Stay based on unable to travel for people having a Non Immigrant Visa, you will most likely get the not approved stamp and 7 days to leave the country.

@Jim ************

Visa rules did not change due to covid.

You applied for the Non Immigrant O-A visa with extra requirements like insurance.

You never could

change that into a Non Immigrant O visa

Just by reading: Ye, you can have a Thai Elite Visa and a Non Immigrant B visa inside your passport. BUT you can only use 1 of them, meaning if you work you must have the Non Immigrant B visa with a work permit and when you do not work you can use the Thai Elite Visa.

MOST important you can not switch every hour or even every day.

Than the only option is to leave the country and start all over again with a new Non Immigrant O visa based on marriage.

What do you call a retirement visa?

Did you enter Thailand using a Non Immigrant O visa based on being over 50 years of age?

Or

Did you enter Thailand using a Non Immigrant O-A (Long Stay) visa?

OR

Did you enter Thailand using a Non Immigrant O-X visa?

OR

Did you enter without visa or Tourist Visa and converted at Immigration to a Non Immigrant O visa based on being over 50 years of age?

Lots of things are called retirement visa, it seems easy but impossible to guess which one is really the visa used.

This is the stamp in your passport:

Non O and 90 days, meaning you have the Non Immigrant O visa and not a Non Immigrant O-A.

No idea where the idea came from that the person needs a new passport, but as ll is clear for him, I close the comments. Feel free to contact the mods or admin if you have a valued contribution to this question.

@Jean-baptiste ******

You cancel the WP and your Extension of Stay using the last day of work as decided between you and your employer. You can do this in advance