Everyone needs heat during Denver winters! Unfortunately, a lot of specific questions need to be answered to provide any useful in information to assist these folks. An attorney will need information about the lease, rent payments, how the maintenance demand has been communicated, on what dates, etc. Your friend should contact an attorney to discuss the specifics of their situation, then an attorney will be able to assist. Since we represent Landlords we cannot assist your friends. I recommend having them contact the Colo Bar Assoc for a referral.