MY MOm Is 58 and had a complete hyterectomy many years ago. She is having alot of brown discharge and air that sounds like a fart coming From her vagi?

Fistula. She may have a fistula from the rectum to the vagina (recto-vaginal fistula), which would be uncommon this far out from surgery, but not impossible. She needs to see a gynecologist, especially one who does urogynecology as they are more adept at the repair of these.
Fistula? She needs to be checked for a fistula (connection) between the vagina and the rectum. A fistula will create a brown discharge as stool enters the vagina and make her pass gas from the vagina. Its also possible that the vagina is open and sometimes traps air that comes out when she moves a certain way. Best wishes!