They also revealed he no longer recognizes most loved ones.
They say his condition has progressed much faster in the last few months than any of them could have anticipated.
Hanna retired from public life in 2021.
He now spends his time at home with his wife Suzy in Bigfork, Montana.
Hanna's family says they are sharing their story because they want others struggling with Alzheimer's to know they are not alone.