When you're that close to death, you're not concerned with making $$$
As someone badly disabled (by an FDA-approved drug, I might add) I can assure you that someone as close to death as Matthew McConaughey's character is not going to be concerned with making money. It seemed his character was doing what he was doing for the money vs. doing it to help people, and that just isn't realistic. Money doesn't matter anymore once you've lost your health, and even if it did--he wouldn't have had the energy required to do all that he did.
PS. This movie was spot-on regarding the useless/inept/corrupt FDA.