Disney Star Tiffany Thornton -- My Hubby's a Drunk ... Just Ask His Mom

Disney star Tiffany Thornton did NOT abduct her two baby sons -- she ran away to protect them from their alcoholic dad ... his own mother tells TMZ.

Musician Chris Carney filed a child stealing report with cops, alleging "The Sonny With A Chance" star abducted their 3-month old and 20-month old boys with the help of his mom, Ruth Carney.

Ruth tells us ... her son has a big drinking problem and recently went to rehab. She says he relapsed recently and "went crazy."

Ruth -- who is the mayor of Hot Springs, Arkansas -- was in L.A. to help Tiffany with the baby, and says when she saw her son acting crazy and drunk, she took Tiffany and the kids and hightailed it out of town to the home of Tiffany's parents in Texas.

Ruth claims Chris knew exactly what was going on during the entire drive, because Tiffany FaceTimed with him daily. She says he was upset.

Chris tells us ... he's not an alcoholic, but rather a social drinker. He says his mom simply freaked out when she saw a beer in the fridge.

In Chris' view his mom is anything but nurturing, calling her an accessory to a felony.