Is the funeral prayer (fard al-kifaya) given precedence over the Sunnah prayer, and must one interrupt the Sunnah prayer for it?

A communal obligation (fard al-kifayah) is superior to a supererogatory act (nafilah), and engaging in knowledge is better than supererogatory prayer. The general principle is to prioritize a communal obligation over a supererogatory act. However, a supererogatory act becomes an individual obligation (fard ayn) once one begins it, according to some scholars. Do not interrupt a supererogatory prayer for a funeral prayer as long as there are others praying over the deceased. However, one may shorten it to catch the funeral prayer. A supererogatory prayer is not to be interrupted except for an obligatory prayer. Thus, it should not be interrupted for a funeral prayer. Nevertheless, it is permissible to interrupt a supererogatory prayer for a valid reason, but it is preferable not to interrupt it.