Source: The Great Interpretation of Dreams (Ibn Sirin)
An angry mother in a dream indicates the dreamer committing a sin or negligence towards her.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
An angry mother indicates God's displeasure or worry afflicting the dreamer.
Source: Signs in the Science of Expressions (Ibn Shaheen)
An angry mother is interpreted as worry. Whoever sees his mother angry will be afflicted with worry.