Zoso is a big A-hole basically.
Anyway, the best advice I can really give you is to tell her to ignore it and that is really hard. Overcoming fear is something not everyone can do as
specially of those things.
I've had my fare share and I really just never opened the door, this is something she should NEVER DO!
Eventually you get over the sounds, the breathing, the constant attack of it as if pinging fear onto you.
I got to a stage where I realized it wasn't my own fear it was it attacking me with fear and putting me into a state/tricking me of thinking it's my
own fear.
Than it went with a full on "Hey I'm in the corner of your room like a black mist of pure evil sh*t" and at that stage I was awake in a paralysis but
was able to break from it in 5 seconds and just told it to piss off and went to sleep.
See if you don't feed it fear or attention they starve, fear and attention is like coc aine for them and they get their rocks off to it.
However, to each person is their own remedy, mine was getting over fearing it and just completely telling it to piss off. For your sisters case she
might need a cleansing, blessing, a protection crystal etc to deal with this and maybe it will take a lot of time.
All I can say is try all known methods and find the one that works for her, I would also assume she's really sensitive to certain things too. They
tend to so to speak target those with one foot here and another foot in the energetic field of what people call spirituality, ether, lucid dreams
etc.
Also the lonely ones are easier for them to target as well they try to use your loneliness against you and pretend to act like they care and than act
out their dominance on you. Such as the case of it saying "You belong to me" etc.
My best advice is this spend more time with her, meditate together but outside in the sun, maybe get a blessing or cleansing done of her room etc. Try
things and don't give up is the most important thing!
Further more ask her this question - Has she ever started to smell a scent of something that smelled close to roses and honey randomly when there was
none around?
If she has tell her to focus on that smell and the calm feeling she felt during it