the ED visa has to be extended every 90 days, and is only valid for one year. The DTV is a five year visa giving you 180 day entry stamp everytime you enter Thailand in those five years.
all you have to show is that you have at least bt500,000, or the equivalent, in a bank account anywhere in the world in your name only, and the paid study contract by a school licensed with the ministry of education. This can be a Muay Thai class, or a cooking class, schedule that you paid for, or a medical treatment program certified by a Thai doctor that will treat you.
a lawyer, or an agent, can not help a person with a 22 month overstay. If they go to immigration they will be arrested, and deported at their expense after paying the bt20,000 fine, with a ten year ban from returning. If they have a plane ticket to fly out, and are on their way to the airport to fly out immediately that day, they will be fined bt20,000, and be banned from returning for 3 years. They have no alternative. An overstay of more than 90 days gets serious very fast, as they include bans from returning. If they go to immigration, or are caught, and not on their way to the airport to fly out, they will not be able to get any of their possessions when they are arrested, and deported, with a ten year ban. It is a serious situation that any way they do it they will get a minimum 3 year ban from returning. Immigration is very strick about this, and there is nothing an attorney can do. This is something the person can not buy their way out of no matter what they do.
he will need a letter from a legitimate business, or his own business, stating his job allows him to work remotely. Without this type of letter he will not get the DTV based on remote working. It doesn't matter how much he gets from the VA, or why. That doesn't count, as he is not working remotely, and has no documentation stating he is. His only option is through the soft power option, and signing up for legitimate classes in Thailand that are approved by the ministry of education. Money coming from the VA makes no difference to any embassy. It does not qualify for the DTV. There are no exceptions to this, as the remote worker category has no wage requirement, only that he would be making a wage by working remotely. There is no minimum wage requirement. There is a work requirement, and that is what has to be proven.
there are no requirements, and Thailand goes by the requirements when you initially received the visa. They have always operated that way. I'll use the ED visa as an example. Initially there were no attendance requirements, but as the abuse showed up, and got worse, they required it being extended every 90 days, with documents from the school, and certified by the ministry of education, that you were attending class, and making adequate advancement, even though it was a one year visa. There are other examples, with retirement visa extensions, and others, but Thailand doesn't change the rules on you until the visa ends, or you relinquish it, starting over. There are still a few people on old retirement visa extensions that are only required to have bt20,000 in the bank, as that was the requirement when they initially got the visa, and it hasn't lapsed. Idealistically your thinking is right, but Thailand operates on reality, not idealism.
just remember, if you get the DTV now, and changes are made in the future, you are grandfathered in, with those changes not affecting you for at least five years your initial visa is valid for. That is how Thailand operates. Currently they are researching, seeing how people are abusing, or trying to scam the system, and will make changes in the near future to address the abuses. This is the Thai way. They did the same thing with retirement visas, education visas, volunteer visas, and will do the same with the DTV as time goes by. Currently there are no after-issue requirements. The only current requirements are to get the visa. There is no requirement that the money stays in the bank. No requirement that you attend any classes you signed up for, or no requirement that you continue working remotely after you get the visa. Requirements will change as time goes by, and some changes are starting to take effect at different Thai embassies already, but the exact requirements when you get it now won't change for the five years you initially have it. That is how Thailand does things.