Can my dad extend his 90-day Non-O visa in Thailand without my presence?

The question concerns whether a father on a 90-day Non-O visa in Thailand can extend his stay for an additional 60 days without his Thai citizen child being present. Responses suggest that while some users indicate he might need to be present for a self-application, others mention that using an agent may allow him to secure the extension without the child's physical presence. However, it appears that proving the familial relationship (visiting Thai relatives) is crucial for this extension.