Resident lying about damage in apartment

[Patty C.]

Hello Everyone!
I have been an apartment manager for five years on a tax credit senior property in Oklahoma. I have an issue with a tenant I hope someone has experienced before, and can give me insight as to how to handle this situation. A little background, tenant is elderly, barely able to care for himself but decides he wants a pet. He moved into a brand new apartment when the property opened. This gentleman is cantankerous, to say the least, and he comes with 2 cantankerous sisters that love to terrorize me. These people operate under " the best offense is a defense" scenario. If there is a maintenance issue in this apartment, and I don't take care of it within 48 hours, the sisters are on the phone to our local housing authority complaining about my inaction. These women complain about everything, including if the postman leaves mail for another resident in the box. I suspect that this dog is urinating all over this apartment. The dog rarely gets walked, and there are puppy pads throughout the apt. The cabinetry when you walk in has water damage on the bottom these people say happened when the porch flooded and water came under the door. This incident was never reported to me. When I was inspecting this unit one day, there was a puppy pad half way up the cabinet, with a urine spray where the dog lifted his leg. Now they keep rugs propped up on the cabinet. Last year there was a leak in the toilet that required a plumber to yank the toilet up and jack hammer the concrete beneath to level the toilet. The concrete was so saturated with urine that the plumbers all had masks on. Since having so many unpleasant conversations with these people, I document every conversation and all contact. The housing authority did their annual inspection of his unit and there was water all over the bathroom floor. Resident and his sister told the HA that the toilet has leaked for months, and I haven't taken care of it. Due to this leak, the bottom of the vanity is damaged, as are the bottom of the bathroom and bedroom doors. I had one call for maintenance in this unit for a broken light bulb and there was no mention about the toilet leaking. My maintenance man had reason to enter the unit two weeks ago for a sewer situation in a neighboring unit and both resident and his sister were there and no mention of a leaking toilet. These people are the type to call the HA whenever I don't take care of something, so I find this difficult to believe. After hearing from the HA, my maintenance man and I went to see this leak. Resident said, and I quote, "I told you I wasn't going to call you about this leaky toilet again." That is in direct violation of the mold prevention statement he signed at move in. The floor looks horrible, but there was no visible leak. I asked him about the damage to the bottom of the doors and he said, and I quote, "At one time the water came all the way out into the hallway." This was not reported to me. I have pictures and documented conversations about various issues with he and his sisters. It is my belief that they are lying about these leaks to cover up the dog urinating on everything. Whatever results from this you can be will involve a courtroom as these people are litigious, and this will end badly. How would you approach this situation. How does one accuse someone of lying without it appearing as such? My corporate office is no help with this situation, and I feel as though I am on my own. What would you do? Thank you so much for your guidance!
Patty