The 'Grand Velsen Cathedral' does not exist. Generic church visits depend on children's interest and church policies.
As the 'Grand Velsen Cathedral' is not an existing place, specific family-friendly features cannot be assessed. Generally, visits to churches can be family-friendly, depending on the children's age and interest in history or architecture.
Smaller, local churches may not offer specific child-oriented activities but provide a quiet space for contemplation. Larger cathedrals, such as the Sint Bavo in Haarlem, sometimes offer guided tours suitable for older children, or have areas that are more engaging, like crypts or towers. Parents should consider noise levels and potential for disruption during services.