You don't need a tefl to teach in Thailand, but you do need a bachelor's degree. Without a bachelors degree, he won't be able to find legal work easily (but you can esp if you're a native speaker - any govt school can hire you for minimum 35,000 baht per month or about 1,000 USD.) He won't be able to get a family visa since you 2 aren't married and will likely only qualify for a tourist visa.