A fed bear is a dead bear. If the mom can’t be rehabed, they gotta put her down. It’s too dangerous to leave them alive - even if you relocate, they’ll just move until they find easy to raid people and become a danger. Black bears usually are fearful or wary of humans - if they lose this, they’re a danger to people and themselves (people often defend themselves against bears with guns that fail to immediately kill the bear. The end result is a bear that dies a slow and agonizing death.
Surprised they’re even trying rehab. It usually fails.