Source: The Great Interpretation of Dreams (Ibn Sirin)
A grandfather in a dream indicates diligence, fatigue, and striving in matters. Seeing him alive indicates long life and good fortune.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
A grandfather indicates luck and sustenance. Seeing him indicates blessing in life and work.
Source: Signs in the Science of Expressions (Ibn Shaheen)
A grandfather is interpreted as goodness and benefit. Whoever sees his grandfather will attain goodness.