Dear friend
Start at the beginning, first pray to the Holy Spirit for guidance and then read the four Gospels, slowly, pondering them and contemplating on them, letting Christ speak to him directly through His Word…Read Catholic Answers online on any point that is striking as something of a problem to him. Advise him to read any book that contains conversion or reversion stories by other people, this will make him feel less alone.
Everyone at some point suffers doubts, it’s not a bad or strange phenomenon, it is a growth process. Jesus called Himself the Son of Man, imagine if He had said, ‘I am God’ they would have crucified and killed Him there and then! But He said ‘I am life’ who is life but God? Jesus said ‘I come not to judge but to give life abundantly’ who can do this but God? Jesus said ‘I and the Father are one, to have seen me is to have seen the Father’…so Christ Jesus slowly and surely through scripture revealed His Divinity, in the Transfiguration showed Himself as Divine, as God. ’ I give my life, I lay it down freely, I give it no-one can take it from me’ all of these words and many more throughout Sacred Scripture reveal Christ as part of the three persons of the Holy Trinity of which is and remains a mystery, but God is truine and Jesus is the second person of the Trinity. In His ressurection He is glorified and in every miracle , in every word that is utter Divine wisdom and in every healing which is God’s realm only and in, by and through God life is healed and ressurected in mind, body and spirit, only God can do this. So Jesus in His ministry of three years revealed His Divine nature veiled in humanity. Jesus slowly revealed He is God.
You husband may benefit from a Spiritual Director and/or regular meetings with his Priest, because they will be able to lead him into a deep reading not only of scripture but of profitable books for his salvation and personal peace.
He may also wish to pray more to the Holy Spirit, (who has become my personal favourite of the Trinity under great and good spiritual guidance of my Priest) who enlightens the mind and heart and leads and counsels us, for our benefit and those around us.
God Bless you and your husband, you remain in my prayers, much love and peace to you
Teresa