lets see what he would do since his children is in front of him, so we can expect him not to show his cruel side, unless he can force them to 'fall asleep' by his eyes
He should kill them and wait until the baby is born from her then kill her in public to make an example to others so they know what happens if anyone betrays the uchiha clan and he should go all out and decimate kirigakure and make them never think about even coming near his kids and clan again