Help please!

 My mom is renting a home in Madison County, AL. She is in a one-year lease. However, the option to purchase a home was made unexpectedly available to her, and she jumped on it. So now we're dealing with a lease-break situation. The leased home is currently almost completely cleaned out and cleaned. 

There is nothing in her lease about breaking a lease. In the Alabama Uniform Landlord and Tenant Act, the lease break stipulations are that the renter is required to continue payment until the property is re-rented, and the landlord is required to put in a good faith effort to re-rent the property quickly. Her property manager is stating that she is required to give a 60-day notice and that she must pay 2 months additional rent as a lease-break fine. In a spirit of good faith, she agreed to pay the rent through December 12th (60 days), but has not and will not agree to pay the additional two months rent unless the property does not re-rent. We have stated this to her property manager repeatedly in e-mails that he is refusing to reply to, we have mailed him printed copies of those e-mails via certified mail and dropped them off at his office. He is refusing to communicate via anything but phone calls.

We have listed the home for rent on Craigslist, and her PM company has listed it as well. They have both had lots of interest and two filled out applications. However her Property manager is telling people that the home is unavailable until December 23rd (it could be ready in about 2 days from now), and he called my mom today and told her that he has an approved applicant, but if she doesn't pay the two months rent then he will "send them elsewhere" and reject future applicants, forcing her to pay the two month's rent because the home is unrented. 

Obviously, this is illegal, but we have no idea what to do. It's just her word against his, as he will only communicate via phone. She has kept detailed lists of all communication between them, but they're just her own lists of what he said via the phone. Nothing we can prove. 

Any suggestions on how to proceed? My mom has been exceedingly kind, trying to re-rent the home as quickly as possible, cleaning it thoroughly, apologizing for the inconvenience, etc.. The property owner would not be out any money if the Property Manager would just allow these applicants to move in. 

*I can post the e-mails we have sent, if it will help.