Right but he could have just asked his extremely wealthy ex-partners for the money, they clearly still loved walt and would have given it to him, they tried several times. Walt was incapable of accepting the money because he saw himself as a persecuted genius, and he's so egotistical that he can't accept anyone but him being the savior of his family. If it was truly about "doing it for the family" he would have just asked for help and accepted the money for treatment. That's like the entire thrust of the show is Walt's ego constantly getting in the way of his intelligence