Not really my place to interpret what your grandmother says but would it be possible that what she meant was for you to stop dwelling on sad emotions and thoughts? Every culture is different but whenever an elder talks kind of vague like that there's usually some other meaning behind it.
Anyway, as for me, the weirdest advice a family member has given me is "If you feel tired, wash your eyes with water."
As a kid I took that advice but quickly realized that it doesn't really help. Later I discover this thing called caffeine, my en-tired world changed, and nothing has been the same since. My family knew kids shouldn't have caffeine, but they didn't know that some soda has caffeine. Heheheh!
Haha!