Can I use my copy of Premier to file both my wife's and my return along with my mother-in-law's simple return at no extra charge?

My mother-in-law is 85 and no longer able to take care of all of finances. My wife has her full POA to handle her finances. That includes the filling of taxes and dealing with Social Security. My mother-in-law's income is only pensions, interest, annuities, and Social Security payments. Total income just under $34,000.