Many a times I [try to] awake my wife for the Fajr prayer however she doesn’t get up, instead, she constantly performs the prayer after sunrise. What is incumbent to do hereafter?

Shaykh Ṣāliḥ ibn Fawzān al-Fawzān:

Her prayer is not accepted. If she does not get up to pray the Fajr prayer you should divorce her. She is not a Muslim. Those who miss the Fajr prayer are not Muslims. If she repents, then Allah ﷻ accept her repentance, so remain with her, otherwise, look for someone else.