Write or wrong – I sympathize with you. I also note that you may want to consult your Rav, or a Rav with experience dealing with similar situations, before rejecting another Derech for your son. Your fight is to keep him a Torah-observant Jew, and that and that alone should be your focus. Externals are nice, and keeping all the “syugim” that have been set up are important, but rejecting paths that have the potential to win the main battle because they don’t preserve the less key aspects may be a case of Tafasta Meruba.
Re: Rabbi Slifkin – he is unquestionably controversial and not for everyone. That being said, please do note that he has Haskamos on several of his books from Rav Yisrael Belsky. Additionally, there are those who reject his books in general, but say that if one has a need for such Hashkafos to answer questions in Emuna, they are acceptable as a Bdieved.
Hatzlacha Rabba,
an Israeli Yid