If the medium does not work, try the following method :
Advise your friend to chant Amitabha on a daily basis. She will
gain 佛光gradually. She can chant Amitabha or Kuan Shi Yin
Pusa for help when she feels the presence of the spirit. Ask
your friend to tell the spirit that she will 超度 him and ask him not
to follow her.
By the way, besides following her, did the spirit disturb her
?
She can go to Ju Shi Ling to 超度, just tell them in details. The
spirit is called 怨亲债主. Many Buddhists used to超度怨亲债主 (your
debtors) during the 7th month regardless of whether the
spirits disturb us or not. During the 7th month, at Ju Shi Ling,
they received any amount for超度.
according to her, like whole day and nite with
her.