Jesus basically answers by telling them that for supposedly learned students of Scripture they are pretty ignorant of the Scriptures and of the nature of God. These relationships did not end. Abraham did not end. He lives on in God's own presence for all time. Abraham lives on, not some spark, or soul, or disembodied spirit.
Love is more powerful than death.
My father died 7 years ago but death could not sever my ties to him. He lives on because of love and, according to my faith and that of Jesus, because of God's love. Be ready to share that comfort and assurance with those who may need it. We fear death for ourselves and our loved ones. Yet, we will face it not as those who have no hope.