By law (2020) you do not have to re-register a tm30 if you are returning to a location within the check-in period of that location. So if your main address is registered with a null checkout date or a date still in the future, then there is no legal obligation to re-register. However, if you need to visit the immigration office for some reason, certain offices require a new TM30 after either/or international/domestic travel. I use CW and do a lot of domestic travel and still utilizing my original tm30.
If your work permit contains your home address, then according to the rules it fulfils the requirement as proof of address. However for the last couple of years addresses are no longer included in the work permit, so the residency certificate would be required. You should also watch the dlt safety video online before you go (not the same video on you tube). After answering some ad hoc questions, print out the QR code that proves you completed it as this generally allows you to skip any ques or appointments to watch the video.
no the problem is that the 100s of 1000's of farangs didn't take the time to understand the tax laws when they moved here. They have always been in place, the thresholds & tax rates etc may have changed over the years, and what is taxable and is not. Those that did take the time, and knew they could avoid tax complications by holding money abroad until the next tax year before remitting it are the only ones effected by the change which was well comunicated at the time. Everybody else is just learning what they should have been doing for years, which is not something the government should have to explain.
According to the law (2020), if you are returning to the same location that you are registered at via the TM30 reporting system within the validity of your stay ( prior to the recorded checkout date) there is no legal requirement to update. However if you need to interact with an IMO, certain offices require an updated version after international travel and/or inter province travel. On a retirement visa there should be no need to reregister if you havent previously had issues with your 90 day reporting.
if they can see your tm30 on the system and it ticks all the right boxes, they won't need to ask where it is. If they dont see one or there is an anomoly, then they want a hard copy.
Your friend should go to the local imigration office and request a residents certificate, and also ask if they will supply a letter stating his intention to get a retirement visa and that he needs to open a bank account. Some offices do this, and some banks will accept the letter.
You need to check your entry stamp in your passport, while you might have a '90 day visa', this only means it has a life of 90 days ("use by"), on a tourist visa they would only stamp you in (allowed to stay) for 60 days.