Hello Theodore,
"How can a disabled person with no marketing skills build a successful business with SFI?"
Firstly can i say what a great question and one that is close to my heart as i am disabled.
It all depends on what the disability is, if you are able to read, and use a computer then there is no reason why a disabled person would have a problem doing SFI.
I really hope this helps and good luck in your business.