Is it permissible to interrupt prayer to respond to a mother's call in an urgent matter?

If the prayer is an obligatory one (fard), it is not permissible to interrupt it unless the mother calls for help and the son is able to assist her, because the right of Allah takes precedence. If the prayer is a supererogatory one (nafilah), it is preferable to shorten it or interrupt it to respond to the mother, because honoring one's mother is obligatory and takes precedence over supererogatory acts of worship.