Retirement if she qualifies. From Thai Embassy site - To apply for a retirement visa, you need to meet these key requirements:

You must be at least 50 years old.

You’ll need to have 800,000 THB in a Thai bank account for at least two months before applying, or show proof of a monthly income of 65,000 THB.

Alternatively, you can combine both savings and income to total 800,000 THB annually.

A valid passport with at least 12 months of remaining validity.

Proof of health insurance that meets the requirements set by Thai authorities. No Criminal Record. No health diseases etc. There's a whole list. Good Luck 👍