My fear for you is as you described the support, it is all word of mouth from self admitted non-business thinking individuals, who are either breaking even or losing money.
That's a good point. Even if the OP's teachers are great at teaching and doing martial arts, and see the potential in him for teaching on his own.... if they're bad at managing the business and are not making money, he should probably take their advice about starting his own business with a large grain of salt.
He should do careful market research, take some business classes or do a lot of reading about accounting/marketing/etc, and talk to a lawyer and probably the SBA (especially if he needs a loan) before starting this venture.
Now, if he just wants to teach a few classes a week at the community center or whatever, and isn't trying to make money off it... well, he should probably still talk to a lawyer and read a book about marketing, but that's pretty low-risk.