It's too bad that more wasn't explained as to how he reached his conclusion. But nevertheless, many Jews believe the Messiah (not Jesus) will come soon.
The New Testament predicts two beasts will come. I believe the second beast is a coming false Messiah.
The first beast is most likely the world leader in Rome (Rev. 13:1ff); and the second beast is the false prophet (Rev. 13:11ff). Reading about the second beast Rev. 13:13 says he does great miracles. And Rev. 19:19 states, "And the beast was taken, and with him the false prophet that wrought miracles before him. . . ." That means the second beast and the false prophet are the same person.
The first beast is never described as doing miracles. But look at what is described for the son of perdition in 2 Thess. 2:9 which states, "Even him, whose coming is after the working of Satan with all power and signs and lying wonders."
Look at Jesus' description of false Christs/prophets: "For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect."
Please notice the location of the son of perdition who is said to perform signs and lying wonders; 2 Thess. 2:3-4 shows him sitting in the temple, which will be in Jerusalem. For the Jews to allow him to reside there it would seem they will accept him as their Messiah. It is inconceivable they would allow anyone else to reside in a rebuilt temple. So, this miracle worker is a false Messiah. Jesus predicted in John 5:43 that they would reject him as the Messiah and choose another in his stead. That is still be be fulfilled, as the Jews have still not yet accepted someone as their Messiah.
The second beast seems to be a false Messiah. Rev. 13:11 states, "and I beheld another beast coming up out of the earth; and he had two horns like a lamb, and he spake as a dragon."
Lamb is a symbol for Christ, and dragon is a symbol for Satan. So, this verse is saying this beast appears like the Christ but his words are coming from the devil; hence, a false Christ.
The one common association used with the word antichrist is denying that a Messiah has ever come in the flesh. 1 John 2:22, " Who is a liar but he that denieth that Jesus is the Christ? He is antichrist. . . ." Of necessity anyone claiming to be the Jewish Messiah must deny that a Messiah has ever come. The Jews are in the spirit of this coming antichrist because they don't believe Jesus was the Messiah, but are still in search of the Messiah.
But most prophetical writers call the world leader antichrist. They also fail to destinguish the son of perdition from the first beast. They tend to link these two characters, found in both the old and new testaments, as the same person, not being able to distinguish which one is being discussed. But both are not the antichrist.
Jerry Falwell came under great criticism about 5 or 6 years ago for saying he believed the antichrist was alive today and Jewish. I agree with Falwell. He is evidently on the correct page as to who should be identified as the antichrist.
I see a number of Jews trying to discredit it, claiming Christians are unreliable and have created a hoax. It goes to show a bit of human nature that tries to find evil in the source because they don't like what is said. Reading the articles, which plainly shows his son denying it, shows them being inclusive. It also mentions it posted to websites linked to the Rabbi. His son probably is reacting in the same way as the other Jews who are answering this question, that is to attack it in order to save a revered name, not really being interested if it's true.