Reader question: How long can I stay in Thailand?

I would be careful about living with family, the rules are the same as in Holland, you live with others, can that influence (discount) your benefits, if there are working people among them, I would first Let me get good information from the UWV.
And don't be surprised if you get a check on yourself from Holland at a given address, it also happened to me three years ago, no fewer than 22 people from the UWV came in pairs of two to various places in Thailand to check the accuracy of the information given. , a few were then confronted with the consequences, with the necessary consequences of refunds and fines. They accused that it was a disguised holiday for UWV employees, and I was not thanked for that.

That's not so easy.
Officially, of course, both the Dutch state, the benefits agency and the Thai immigration service set their requirements.
The least common multiple (if you remember that from school) is what “everyone” allows.
Another matter is whether you want to take the risk of going "not quite according to the rules". In that case you run the risk of losing your benefit in the Netherlands or having it cut, or being deported from the country in Thailand.
The rules:
WAO: I think if you want to take a holiday abroad for longer than three weeks, you should first ask or report this to the GAK.
If you would like to emigrate officially, this must also be reported to the GAK and an official re-examination will then take place “to see whether you fall into the same disability category for the country where you are going to live than you are now (80-100 %) with any adjustment of the benefit amount. It sounds strange, but that's how it is. (I don't know how seriously people take this nowadays, but there are also calls to adjust benefits to the standard of living of the country where the benefit recipient lives, so first carefully inquire in a roundabout way.)
If there is permission to emigrate, emigrating to a social treaty country is better than to a non-social treaty country. In that case, the benefit will not be reduced for non-medical reasons.
Thailand is a social treaty country and indeed control over the disability benefits will then be transferred to the Thai SSO (the question is what they will end up with, there were many initial difficulties and much has been reversed from the control exercised by the SSO on AOW benefits and that was only an administrative check whether one was employed, with disability there is also a medical aspect, the Thai have never heard of that, getting money because you can't work).
Visa for Thailand
To obtain a non-immigration retirement visa, the age requirement is greater than or equal to 50 years. (and the mentioned income requirement) However, a visa based on marriage to a Thai woman is possible, I think there is no income requirement there.
Dutch civil status:
I don't know how long you can be abroad without losing your "address". Civil status questions.
Conclusion:
I think the possible problem lies with the GAK and their medical service. Ask what is possible there first. Be prepared that a doctor's statement is likely to be requested if you argue that the Thai climate would be better for your illness.
Note:
1. If you want to avoid a re-examination and/or want to keep your hands free to possibly "go" longer than is actually allowed, it seems better to request that information anonymously (e.g. via a social lawyer)
2. When presenting to authorities, you usually get a more willing ear if you present it as a one-off.
3. In the case of permanent immigration, the aforementioned points are indeed loss of old age pension (but can be compensated by voluntary old age pension) and loss of health care act. (Very important, as a WAO person it is probably less easy to take out a new affordable health insurance policy without exclusions) WAO is very stigmatized, I was once refused a very small mortgage a long time ago with the argument: “Sir, you have WAO and then you have a higher suicide risk”
A positive note is that with an income as you indicate with emigration, a tax and levy benefit also arises.