Once I went to Niagara Falls to hear BJ Thomas, but unfortunately he didn't show since the promoters stiffed him. As much as he loved singing christian songs, and some of those albums contain some of his best work, he needs to pay the bills and feed his family. Even though he had many hit records, many people in the business ripped him off. The music business is famous for that.
He still sprinkles some of the christian tunes into his concert programs such as What a Difference You Made in My Life.
Christianity saved his life and his family at a time when he was down and out.
I have no doubt, that he is still a christian, but that doesn't mean that should be all that he sings about, or that he should be a bible thumper either.