I would answer that he is incorrect because the tithe precedes and transcends the Jewish nation. Melchizedek received tithes; he wasn't a Jew and lived before the Jewish nation existed. His priesthood preceded the levitical priesthood and was superior to it. And Jesus is a High Priest according to the order of Melchizedek.
Tithe, like the distinction between clean/unclean meats and the prohibition to consume blood were all principles which preceded the old covenant. Thus, they weren't automatically abolished when the old covenant passed away.