What
Drunkenspleen said. Only the Challenger and Challengee can participate in the fight, so the Wolves are unable to join in.
Fenrisian Wolves as Wargear got a little weird. In 5th edition they were treated as a separate unit that had to stay within 2" coherency of the model that purchased them, meaning you often had 3 units in combat (the wolves, the
IC, and the squad the
IC joined). In 6th edition you do not treat
ICs as separate units anymore, so it seems the Fenrisian Wolves become fully part of the unit the
IC joins. You still have to be within 2" of the
IC, but they can take wounds before any of your Power Armor does (or absorb some AP2 shots).