The cat can be domesticated but it will take a long time and much patience.
They should try sitting quietly in the room with her while she is eating. Do
not attempt to touch her or pick her up. They need to gain her trust which
will take time and patience. Also, they can buy those feathers on a wand and
try to engage her in interactive play. I had a feral cat and it took about a
year for me to be able to pet her and pick her up.
Gail

She'll have to spend lots of time in the room with the cat. Have her
take a book and sit in there and read. The more time she's in there --
the better. It helps to talk to the cat like she's doing, too.

Food works wonders too. Have her throw threats to him without getting
too close. He needs to know that she gives him good things.

When she thinks he's tolerating her in there, she can scoot a little
closer and read. Don't continually make eye contact, it can sometimes be
interpreted as a threat.

When she's close enough, have her throw some good treats to him (like
real chicken,) then try to hand him a piece. It's a major sign of trust
when he eventually takes a piece of food from her hand.

Later after that, she can try to touch him and pet his back.

It takes a lot of time, it could take several weeks yet, but it's so
rewarding when they start to trust.

That's great that she's helping this cat.

Rhonda

Yes, they can be domesticated but it takes awhile.  Some may always be
nervous pets but still will be good pets.  Tell her to put on some *soothing*
music in the room also, a radio perhaps, quietly though as a feral won't be
used to it.  When your sister looks at him, tell her to close her eyes very
slowly, then slowly open them again and repeat a few times.  This is very non-
threatening to them and shows friendliness.  Of course, lots of good food
helps too, a full belly will make him more sendentary (just in the beginning
please - too much food later might lead to weight gain).  From my experience,
some ferals think a toy mouse is the real thing and will eat the tail, etc.
so might want to be careful with the toys.  Remember, they have no experience
with playing; cats living outside have to spend most of their time hunting to
survive.  To rescue and tame a feral cat will be a very rewarding experience
for her;  what a great person for doing this.

NanCe

I have two former ferals that I trapped at 6 and 8 months old.  The 6
month-old is now 12 years old and the 8 month-old is now 6.  The 6 month-old
took about 3 months to settle in and the 8 month old took about a year.
Usually, but not always, the older the cat the longer it takes to tame.
However, individual personality and experience with humans as well as
genetics play a large roll
in the taming process.

Its very important that your sister doesn't force herself on the cat or try
to rush the taming process.  Let the cat come to her on her terms.

Phil