Grizzly Sleuth by Eve Langlais

Only one woman is allowed to poke this bear.

Idris has a problem. He shifts at the slightest pain, which is kind of inconvenient when it happens in a place where you don’t usually see bears, like a grocery store. Since these incidents keep happening, he ends up starting a new life in Russia, a country that doesn’t mind big furry butts.
Not knowing the language and his desperate attempts to keep his secret make for a lonely existence. But that all changes when his local bar puts on a special show featuring Svetlana and her amazing ursine, Yuri.

Turns out, he’s not the only shapeshifting bear in the world. However, the brother and sister duo aren’t interested in befriending Idris… until they find themselves in trouble. Trouble that also affects Idris.
Seems the General and Dr. Levy have a new lab in Russia, and they’re looking to fill it with unwilling patients.
When Idris and the siblings are nabbed and forced to live their worst nightmares, they fear they’ll never escape. At least Idris and Svetlana are together, but for how long?

Their only hope is that his old military mates come to the rescue, but will they be willing to risk their safety to save Idris and the woman he loves?