But they are not Catholic.
No, but they are an example of an amalgamation of the two. In a sense I might term them as Catholic Buddhists. They are primarily Buddhist, but they embrace some things in Catholicismthat they see lacking in their own faith. By extension, perhaps the person who considers herself a Buddhist Catholic is indeed primarily Catholic but brings in some things from Buddhism, such as meditation as has been pointed out.
I don’t know if that was the intent, I’m just suggesting it as a possible interpretation of her use of the phrase.