Clearly for now he values being a Dim over being a Roman Catholic. But he is at the first step that sometimes leads to conversion. He will fight to change his party maybe and then eventually see it can not be done.
Such as it is with Islam. There can be no "reformation". Mohammed was the "last prophet".
Those who want to reject "radical" Islam, jihad, slaves, the 3 tiered legal system, etc. must reject Mad Man Mo's cultist interpretation of the Judeo-Christian text and return to the original (and unchanged) source.
Muslims who want "reform" should seek to become Jews (if they still refuse to accept Jesus as the Son of God) or Christians.
The deep seated antisemitism among even "moderate" muslims will mean few conversions to Judaism. Too much of a turn around of heart and mind.
Some Democrats face the same challenge with becoming a Republican.