About citizenship if i have been here 15 years legally?

My friend is In the process of getting permanent residency, but the lawyers are taking too long and too much money, he seems dumb founded when we make the inquiry and we can't bug him too much considering it is all up to him to a degree, they have a work authorization card giving them permission to work while the admission is being put in. What i would like to know is, is their some kind of law that applies to Immigrants that have been here for 15 years who have payed taxed every year and done everything everyone else has who was born in the U.S.A, because time is running out and the lawyer does not seem to care(Going to another lawyer would be too costing and who knows they might be worst). PLEASE CITE THE INFORMATION, tired of seeing bias, ignorant people and their opinions, e.g: "Go back form where you came", i would appreciate FACT and citation, your personal negative opinion are not needed. Thank you in advance.