For the rabbi to faithfully and honestly answer the Isaiah 53 question he will need to confess that Jesus of Nazareth was and is the subject of that scripture; and in doing so, declare his faith in and fealty to Jesus the Christ of God; the crucified and risen Savior.
Give a listen. Bible in “depth.” When he brings up something controversial, just ask your pastor.
(That’s why it’s better to takes notes about every trick the rabbi tries to pull.)