Technically your child requires a valid visa of their own to remain in Thailand with you.

However there is no enforcement on children until age 15.

So a child can remain in Thailand with parents on overstay without fear of fines or bans.

This will not cause problems with Thai immigration.

The evisa routes to the embassy you are applying at.

So you are dealing with the embassy.

For a standard Thai company.

51% Thai ownership

Minimum 2 million baht capital and

4 Thai employees to get 1 work permit for foreigners.

Some business is Thai reserved.

Your ability to work even in your own business will be limited.

There are agencies that can guide you and for the right money work arounds.

@Brandon ***********

has given you the correct advice.

You may DM me if you like and I will walk you through possible options.

BUT you cannot use income, period.

You will need to use banked funds for whatever your initial visa will be.

However you can also see if the US embassy will still allow a non-o 90 day based on retirement AND a dependant 90 day non-o based on visiting non Thai family.

This way you would only need 800k total for 2 of you.

The US and CANADIAN embassies have allowed this, I don't know about 2025 however.

There are a few ways to do this.

@Colin ********

what you are trying to say is:

If you have a non-o-visa reason for extension is married to Thai, when you partner passes away, your reason for extension is gone.

You will have to change your reason for stay to something else.

It will depend on age, finances etc.

You would switch to:

Take care of Thai child.

Retirement.

Maybe dependant of your Thai child.

Nonb work

Or whatever you qualify for.

Technically when you spouse passed that's it.

Immigration is sympathetic, will try and help.

A letter of support is in regards to the 500k needed in the bank.

The support would be proof of funds and "a promise to pay" for you if you cannot.

From family, work, friend etc.

Yes Phuket Airport does also charge more.

A non-o will only get you 90 days then a 60 day visit Thai family.

5 months.

IMO not necessary as you will need 1 border bounce to get 6 months anyway.

I would:

Enter visa exempt 60 days.

Do a border bounce, some time after 30 days to get to 6 months ,(no extension on this 1st entry)

Then:

Entry gets 60 days.

Then extend 30 days locally.

Then extend 60 days visit Thai family.

7 months no issue.

And you won't have to apply for anything.

Here is a list of approved insurance companies:

Letter of support would come from someone other than the facility being used.

Her mother, her employer, maybe a family friend, etc.

Having the 500k necessary.