My Wife Hates My Parents. What Should I Do ...

When I tackled my Mum about it she denied saying some of the things she was accused of saying and ended up paying for a polygraph test to prove it. It was all petty stuff tho which was things like saying me or my sister were stupid, that she would check on my wifes hygeine (what ever that ... Then we had to rush away to see a sick relative and couldnt take our dog so we asked if they could pop over and let him out which they did tho by the time they did, he'd done a poo! ...