take his Proof of Income Certification by the Norwegian Embassy in Bangkok to be further legalised at the Consular Department, Thailand MoFA (Chaeng Wattana)....
Hey, Thailand is a piece of cake conpared to USCIS+State Department (USA), OFII+MEAE (France), UKVI+FCDO (UK), or Home Affairs+DFAT (Australia)....
you can't hire relatively cheap agents to do visas or immigration things for you, you try to do things by yourself, but the bureaucratic details are confusing, everything is precise and no slack or leniency given, the backlog, wait, and queues are super long (years, even decades), and fees super expensive....just sayin'
in fact, so many want to travel freely, but because of visa or immigration queues (in the 4 example countries), they have to stay in-country for years to get approvals....
There is no defined "limit" to free visa exemption (60 days) entry into Thailand via any method of travel: land, air, sea, but any and all entry into Thailand is at the discretion of the Thai immigration Officer....
From my personal perspective, I understand that what is specifically prohibited, among other things, are specific occupations reserved for Thai citizens.
Having said this, of course the scope can be much broader and the discretion of the Thai Police/Thai Immigration Police Officer is a major factor, but is really the occasional activity of gardening on the property that is titled in the name of your Thai spouse or performing some maintenance activity within said property prohibited by some particular Thai law or Thai regulation?
If truly so, then I stand happy to be corrected and informed of my misunderstanding, but do quote such particular Thai law/regulation....
Well, doing an occasional activity within your own home/premises vs. performing labour for wages/salaries or profit or defined renumeration are two different things about what is "work"....