The author then makes some claims about Jesus not being a prophet which we’ve already addressed, and about Jesus not being a son of David, which is just nonsense. The genealogy is there in Matthew / Luke, and this argument completely ignores the fact that person who is a son by adoption is as much a part of the family as one who is a son by natural birth. Jesus is even referenced as the son of Joseph in the Bible. The Jews of this time weren’t concerned with DNA, the primary concern was being a member of the family. Adoption fulfilled that role, and Joseph adopted Jesus thereby making him a descendant in the line of David.
There last point under the second header is Torah observance. They claim that Jesus didn’t lead to observance of the Torah. We would counter by saying that Jesus fulfilled the covenant of the Torah. That is very different from changing it. The moral laws are all still in place, it is the cultural laws meant to set the Jews apart from the Gentiles that have been removed because there is no long any purpose for them under the new covenant. The gentiles have been welcomed into God’s family as children, and so the cultural distinctions are no longer needed. Incidentally, we do see Jesus fulfilling all the commands of proper Jewish observance, including circumcision, fasting, and celebration of the yearly feasts, along with temple attendance and pilgrimage to Jerusalem.
From there the author talks about mistranslations. The Virgin Birth is one that has a long debated history. I believe the translation is accurate, but even if it does only mean young woman, Mary still qualifies, so that’s a pointless argument. The suffering servant argument is likewise specious. Even if it does refer to the collective Israel, there is no reason to conclude that it only refers to the collective and could not similarly apply to the singular Messiah. The pains Jesus suffered are so explicitly similar to those listed in Isaiah that it would be hard to argue there was no connection.
Their last point is that God spoke to Israel as a nation instead of through individual revelation, and this is just a blatant falsehood. Apart from a handful of instances, every time God talks to the nation of Israel it is through a singular prophet, whom the people have accepted is speaking on behalf of God. They have no proof apart from the signs which accompany the revelation (thereby debunking their whole “we didn’t care about miracles” bit), and the person’s word for it that this is what God is saying. Jesus, as with the other prophets, accompanied his revelation with signs and miracles exactly like those foretold. (healing the sick, raising the dead, etc.). Jesus’s revelation was also intended for the whole of Jerusalem, as He taught to them many times, and then had the disciples go out and teach them accordingly after His resurrection. This argument is just flat out wrong, and borderline dishonest.
Sorry for the wall of text. I hope this helps.