Is it sunnah for a man to align his feet when standing for prayer facing the qiblah?

Facing the Qibla with one's feet is an obligation (wajib), not a sunnah. It is recommended (yusann) to keep them slightly separated, by about a span (shibr), and one should not separate them excessively. Facing the Qibla with one's feet is a condition for the validity of the prayer (shart fi sihhat as-salat); the prayer becomes void by neglecting it.