A friend of mine has adopted an ex-feral cat and
she's now keeping him in a small room in her house.
He's still hissing at her when she enters the room
and she's worried that if she lets him out of that
room he will run away when somebody opens the front
or back door of her house. But I think that he may
be unhappy being kept in a small room by himself
most of the time.

Any suggestion will be appreciated.