Nothing wrong with your questions or wanting to be involved but you are trying to make sense of the American tax laws having spent no time studying them.
Begin with obtaining the ITN number. During the wait there is time to figure out taxes.
Ok, this is like beating a dead horse, but I will do what no others have done to solve your problem. You need a job. He needs a job. You are broke. Now, I ask you to keep an open mind. I know that you are educated and might consider what I am about to propose as silly. But, I will go ahead and tell you anyways. Our economy is in the dumper. Manufacturing has all but vanished. One industry that has stood the test of every economic down turn has been the trucking industry. I know doctors and lawyers who gave it all up to drive big trucks and they love it. I hope you are a doctor or a lawyer. You can be working within two weeks if you want. Both of you can travel the country and get paid well for it. As a matter of fact, both of you can learn to drive and be making $120,000 within two years. You think I am lying? That will be your problem. Investigate some trucking schools in your area. Find out, by going to some truck stops in your area and talk to couples who are driving together. What have you got to lose but a few hours of your time.