Here is a fantastic short video on jews for jesus. I highly recommend it. Check out minute 1:10 and 1:30, you will see images of the jews for jesus training manual, and you will see that types like this convert zeb are not friends of Christ. They scatter what Christ gathers.
This video calls them inverted marranos. Outwardly the marranos practiced catholicism, but inwardly at home went back to being jews. These jews outwardly practice judaism, but inwardly they try to be christians. Both are a fail and a damage to the church.
Here is my opinion of the matter. Judaism is the extremist of all extremist religions. However, they also have the capability of settling in between that extreme. And, that is where these jews for jesus fall in. However, Christ separates the sheep from the goats. And, these jews for jesus no matter their disposition, are not Christ. So, all of this is an abomination to Catholics.