Shannon, what you wrote in your first comment is pretty much exactly what I would have said (albeit not so elegantly). Even as I clicked to read the comments I anticipated the debate that you had been inevitably pulled into (and handled quite brilliantly). I would hope to have you on my side in any such debate (and they seem to happen all too frequently).

The poor child, with all this fallacy being thrown at her in a misguided attempt to hurt the other parent. At least, if he did convert to Judaism to marry his wife and then baptised his child, he seems not to regard religion particularly seriously, and would hopefully educate the child in a balanced way if he got custody.