This being would appear so that she or her family members could see it but would not reveal its face. On such occasions, she felt no fear because the yin being did not cause any trouble, but rather, it would often wake her up to remind her to cultivate without tardiness. She then would recite the Buddha’s name. When she recited the Buddha’s name, the yin being would leave.
The yin being seems to have no ill intentions. However, that could change down the road, especially at the time of death.
It can be dealt with from two sides.
First, she should bring forth the mind of kindness and compassion to help liberate the yin being, to help it detach from her. If not, it might persist into future lives. She should recite the Buddha’s name and dedicate the resulting merit and virtue to help the yin being attain liberation. If she feels that her gongfu is inadequate in helping others obtain liberation, she could request a rebirth plaque for the yin being. That is one of the ways to use the Dharma to turn attachment into liberation.
From her side, she is right in understanding that from this experience, at the time of death, obstructions can arise to prevent her rebirth. If she can, she should get a rebirth plaque for herself to pave the way (to resolve obstructions) and accrue rebirth blessings.