Source: The Great Interpretation of Dreams (Ibn Sirin)
A grandmother in a dream indicates the world or asceticism in it. Seeing her alive indicates fertility and a good life.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
A grandmother indicates the end of worries and relief. Seeing her indicates blessing.
Source: Signs in the Science of Expressions (Ibn Shaheen)
A grandmother is interpreted as goodness. Whoever sees her will attain goodness.