Can astrology be so sure?

I'm going to narrate a story that I find it hard to believe. But certain happenings in the past and experiences narrated by friends make it difficult to ignore the story in toto. And so, here I go. Ramakrishnan is a relative of mine who's genial and a gentleman, who can never hurt even a fly! His love for his 96 year old mom is touching and a lesson, indeed, for all of us who believe that it's not possible in present day circumstances. He's been visiting every temple around, doing 'pooja' for his mother's longevity. The old lady - she looks pretty even now - is weak and more or less restricted to her bed. The nurse looks after her immediate needs, carefully supervised by Ramakrishnan, who has stopped going to work under the pretext that his mother needs him all the time! As bystanders, we realise that the old lady's faculties - functioning within normal parameters - have started giving way and one feels sad, that, as of late, she finds difficulty in swallowing and therefore, resents food. Having been in the pharmaceutical field, the son keeps changing medicines and their dosages in his eagerness to keep her going. And now comes the astrology bit. An astrologer seems to have told my cousin - Ramakrishnan's wife - that the old lady's soul is unable to leave her body thanks to all the 'pooja' that have been conducted and if and when the old lady departs for her eternal journey, her son will also surely follow. The nurse has reported that the old lady keeps asking her as to whether she'd like to accompany her. Now, that's the eerie part of the story. To me, it's absolute hogwash and should be trashed without hesitation. But can I be so sure? Yet another mystery about life, perhaps?!