Thank you. Even that book indicates that the evidence that President Lincoln was a Catholic is questionable. The fact is that there are no parish records to substantiate the claim and it seems the evidence is based on rumor and fable.
I put this on the same level of confidence as the oft repeated claim that President Washington converted to Catholicism on his deathbed. These stories are popularized by people who have a desire to "prove" that the Catholic Faith has been very influential in the founding and building of the United States and to "prove" that the U.S. is, at heart, a Catholic nation.
I think this claim is mere poppycock.