understand that he has been tagged in the immigration computer system, and as soon as his passport is scanned, his picture is taken, and he's fingerprinted, his whole history comes up, and with him being rejected once already, that is the first thing that comes up. Unless he gets an appropriate visa, he will not be let back in. He has been identified as trying to live long term in Thailand as a tourist. It doesn't matter how many times he has crossed out, and returned. There is not a set in stone number. It is purely at immigration's discretion, and they are very technologically advanced, at every entry point.
actually Thai home internet speed, and usage is rated 4th in the world, with an 85% usage rate. Thailand's internet, and usage availability is very advanced, and not 5-10 years behind as you think. This data is easy to find with simple searches. As a side note, percentage wise, more people in Thailand use Facebook than any other country in the world. Thailand's internet is very modern, and used.
your best opportunity for that is in the Chaeng Mai area, and the small growers, as the big commercial growers don't network. Thailand let's free market work, and the industry now is very competitive, and extremely saturated, but good luck. Just remember one important thing about Thailand. It is not a training ground. Only the best make it here, and survive.
you've definitely been living in the past. Thailand does not keep technology, and modern science from the masses. That is a pure misunderstanding on your part. Thailand is number one in the world in lots of agricultural sectors. They are the number one exporters in the world of fresh, and frozen chicken. The number one exporters of pineapple. They were number one in rice exports, until Thaksin and his sister's government screwed that up. They've got patents on the top quality rice strain in the world, with their hom mali, fragrant jasmine rice. There are others too, like the number one exporters of latex rubber, longan fruit, durian, and a few others. They are actually the leaders in modern science in lots of areas, and not keeping technology from the masses. Although lots of foreign people are fed an image of a farmer plowing his fields with a water buffalo, that hasn't existed for over 2 decades in Thailand. It might be a good idea for you to modernize your thinking about how advanced Thailand really is. It is not some oppressed backwards third world country, that seems to be your impression. Thailand is very advanced, and the world leader in many areas, including agriculture, and pride themselves in this fact. Thailand has government programs that promote innovation, design, and modernization, at every education level. Most foreigners don't even know these programs exist, and at a wide scale. In Bangkok alone there are 52 universities, and that's not counting the trade schools. Thailand's economy is very modern actually, contrary to what you believe.
Be fully aware that every agriculture job is a restricted occupation for Thais only, except in some cases as a consultant only in any commercial for sale operation, and cannabis is an agriculture product. You can't even show someone how to use a shovel, or how to apply nutrients. You can only verbally consult legally. Also understand that some of the best, and most experienced growers, and plant science specialists, from all over the world came here to grow when it became legal. Ideally you've got the right idea, you're simply two years too late though. There are growers here supplying the medical cannabis market in places like Spain, and Germany, that is heavily tested, and controlled by their governments when they buy Thai products. Like I said, you're about two years too late.