أحسن الله إليكم If a person made an oath to pray Tahajjud and he set the alarm and took the measures however either his alarm didn’t ring or he didn’t hear it and woke up after Tahajjud time ended, should he still pray it although the time ended, and if he didn’t is there kaffarah upon him?

Ustadh AbdulAziz al-Haqqan

Yes give kafarrah better.