went back and rewatched the ending. The mom does show up in one shot after the zombie fight, as the bomb goes off, and they are hit be the shockwave. shes in the cockipit passenger seat. holding on.
when the heli hits the dirt, the cockpit has a huge spike into the windshield, showing TIG 100% dead. when daughter gets up, she walks over to the cockpit, again showing it, impaled. and we even get an interior shot, showing her impaled.
Theres several out of focus shots showing the cockpit. its possible, but not clear.. the mom is show dead, hanging through the window. its out of focus. can't tell for sure its her.