What happens to a Non O Guardian visa holder if they lose their part-time job in Thailand?

So your partner is on a 90 day Non-O visa based on being the parent of a foreign child enrolled in school on an ED visa and by meeting the proof of the 500K baht banked ?

IF they haven't gotten their yearly extension yet for the reason they currently have their Non-O visa there is no way to change to a Non-B inside the country. <- You can't change VISA types inside the country (other than Tourist to Non-Imm).

They can't go from a 90 day Non-O to a new Non-B and they can't get an extension on that Non-O for any reason other than what the visa was issued for (being the foreign parent of a child on an ED visa)

They'd have to leave the country, get OFF this Non-O visa, then either come back in free stamp entry and have the employer supply the documents to apply for the 90 day Non-B visa at the immigration office inside the country OR they would take those documents to a nearby thai consulate and get the 90 day Non-B issued there

Now as far as what happens if/when they lose the job..

IF they were on an extension of stay based on employment, AND

they met the proof of funds requirement to get the extension based on a foreign parent of a child on an ED visa,

They could cancel the employment extension and immediately apply for a new extension based on raising foreign child.

UNless I'm greatly mistaken there is no way to get a Non-B visa/work permit for "part time" work.