Thailand question: Can my acquaintance soon live in Thailand?

Dear questioner,
if that 'friend' retires then I really do not see why he should not settle permanently in Thailand. The disability benefit will then expire anyway because he will retire.
What the consequences will be for his AOW: that has been discussed and described here many times, ad nauseam.

Dear Guus, 5 comments to help you on your way:
1- your friend must deregister from the municipality if he emigrates in due course. The municipality passes on its new address to the SVB. He pays his benefit to his NL or TH bank account.
2- As of January 1, the AOW amount for someone who lives together is Euro 974. Only wage tax is withheld. No more premiums and no Health Insurance Contribution. You will then have about Euro 880 net left. Please note: you may no longer participate in NL health insurance. If he has accrued pension through his work, he will also receive that benefit as usual, see 1.
3- In due time his wife will be entitled to state pension herself, she will receive 2% of Eur 974 for each year she lived in the Netherlands. So suppose she lived in the Netherlands for 20 years, she will receive Euro 67 gross on her 390th year. She will lose about 39 euros in payroll tax. If she has accrued pension through her work, she will also receive this on her NL or TH bank account. Also count about 10% wage tax here.
4- Before he emigrates, he naturally applies for a Non-Immigrant-O visa. After entry, he may stay for 90 days, and then extend. Always for a period of one year. To get such a year extension, he must prove with documents that he is married and has at least 40K baht per month in income or 400K ThB in a TH bank account. Or both options. If you want to know more about the conditions that apply to visa and residence, please ask RonnyLatYa your question via the contact form.
5- You report that your acquaintance currently receives a disability benefit. This means that he has a chronic illness or condition or other type of failure. Participation in Thai health insurance is voluntary and very expensive. You can request the necessary information about this via File Medical Expenses in Thailand, at the bottom left of this site.
6- Keep in mind that with all companies, the conditions, illnesses and ailments you suffer from are excluded (!) from coverage. Actually, such an insurance is of no use to you at all, but that is my personal opinion. I therefore deposit the premium that I would otherwise have had to pay into my own pot.